TAJO-1909: Eliminate remained explicit diamond expressions.

Signed-off-by: Hyunsik Choi <[email protected]>

Closes #802


Project: http://git-wip-us.apache.org/repos/asf/tajo/repo
Commit: http://git-wip-us.apache.org/repos/asf/tajo/commit/5d470bc6
Tree: http://git-wip-us.apache.org/repos/asf/tajo/tree/5d470bc6
Diff: http://git-wip-us.apache.org/repos/asf/tajo/diff/5d470bc6

Branch: refs/heads/master
Commit: 5d470bc6001bb4fe096d7a8d221e51c18c683899
Parents: ccca8c6
Author: Dongkyu Hwangbo <[email protected]>
Authored: Thu Oct 8 15:02:58 2015 -0700
Committer: Hyunsik Choi <[email protected]>
Committed: Thu Oct 8 15:21:11 2015 -0700

----------------------------------------------------------------------
 CHANGES                                         |  3 +++
 .../tajo/catalog/store/HiveCatalogStore.java    |  8 +++----
 .../catalog/store/TestHiveCatalogStore.java     |  2 +-
 .../tajo/catalog/store/AbstractDBStore.java     |  4 ++--
 .../apache/tajo/common/type/TajoTypeUtil.java   |  2 +-
 .../org/apache/tajo/datum/IntervalDatum.java    |  2 +-
 .../java/org/apache/tajo/util/BytesUtils.java   |  2 +-
 .../java/org/apache/tajo/util/ClassUtil.java    |  2 +-
 .../java/org/apache/tajo/util/KeyValueSet.java  |  2 +-
 .../org/apache/tajo/util/ReflectionUtil.java    |  4 ++--
 .../apache/tajo/util/ShutdownHookManager.java   |  4 ++--
 .../main/java/org/apache/tajo/util/TUtil.java   | 22 ++++++++++----------
 .../util/graph/TestSimpleDirectedGraph.java     |  2 +-
 .../util/graph/TestSimpleUndirectedGraph.java   |  2 +-
 .../apache/tajo/validation/TestValidators.java  |  4 ++--
 .../planner/TestEvalNodeToExprConverter.java    | 12 +++++------
 .../tajo/engine/planner/TestLogicalPlanner.java |  4 ++--
 .../apache/tajo/master/TestRepartitioner.java   |  2 +-
 .../master/scheduler/TestSimpleScheduler.java   |  2 +-
 .../apache/tajo/querymaster/TestKillQuery.java  |  2 +-
 .../ws/rs/resources/TestClusterResource.java    |  2 +-
 .../ws/rs/resources/TestDatabasesResource.java  |  8 +++----
 .../ws/rs/resources/TestFunctionsResource.java  |  2 +-
 .../tajo/ws/rs/resources/TestQueryResource.java | 12 +++++------
 .../rs/resources/TestQueryResultResource.java   |  8 +++----
 .../ws/rs/resources/TestSessionsResource.java   |  6 +++---
 .../ws/rs/resources/TestTablesResource.java     |  8 +++----
 .../tajo/engine/codegen/EvalCodeGenContext.java |  2 +-
 .../tajo/engine/codegen/EvalCodeGenerator.java  |  2 +-
 .../engine/codegen/ExecutorPreCompiler.java     |  4 ++--
 .../engine/planner/PhysicalPlannerImpl.java     |  2 +-
 .../engine/planner/global/GlobalPlanner.java    |  2 +-
 .../planner/global/ParallelExecutionQueue.java  |  4 ++--
 .../engine/planner/physical/HashJoinExec.java   |  2 +-
 .../planner/physical/PhysicalPlanUtil.java      |  2 +-
 .../apache/tajo/master/rm/TajoRMContext.java    |  2 +-
 .../tajo/querymaster/DefaultTaskScheduler.java  |  6 +++---
 .../apache/tajo/querymaster/Repartitioner.java  |  6 +++---
 .../metrics/reporter/TajoMetricsReporter.java   |  2 +-
 .../java/org/apache/tajo/worker/FetchImpl.java  |  4 ++--
 .../java/org/apache/tajo/worker/TajoWorker.java |  2 +-
 .../java/org/apache/tajo/worker/TaskImpl.java   |  2 +-
 .../apache/tajo/jdbc/TajoDatabaseMetaData.java  | 14 ++++++-------
 .../org/apache/tajo/plan/ExprAnnotator.java     |  2 +-
 .../org/apache/tajo/plan/ExprNormalizer.java    |  6 +++---
 .../org/apache/tajo/plan/LogicalOptimizer.java  |  6 +++---
 .../java/org/apache/tajo/plan/LogicalPlan.java  |  4 ++--
 .../org/apache/tajo/plan/LogicalPlanner.java    |  8 +++----
 .../org/apache/tajo/plan/TypeDeterminant.java   |  2 +-
 .../apache/tajo/plan/expr/AlgebraicUtil.java    |  2 +-
 .../org/apache/tajo/plan/expr/EvalTreeUtil.java |  6 +++---
 .../plan/exprrewrite/rules/ConstantFolding.java |  2 +-
 .../exprrewrite/rules/ConstantPropagation.java  |  2 +-
 .../tajo/plan/rewrite/BaseSchemaBuildPhase.java |  8 +++----
 .../plan/rewrite/rules/AccessPathRewriter.java  |  2 +-
 .../rules/CommonConditionReduceRule.java        |  4 ++--
 .../plan/rewrite/rules/FilterPushDownRule.java  |  2 +-
 .../rewrite/rules/InSubqueryRewriteRule.java    |  2 +-
 .../rewrite/rules/PartitionedTableRewriter.java |  4 ++--
 .../rewrite/rules/ProjectionPushDownRule.java   |  4 ++--
 .../tajo/plan/serder/EvalNodeSerializer.java    |  2 +-
 .../tajo/plan/serder/LogicalNodeSerializer.java |  8 +++----
 .../tajo/plan/util/EvalNodeToExprConverter.java |  2 +-
 .../org/apache/tajo/plan/util/PlannerUtil.java  | 10 ++++-----
 .../tajo/plan/verifier/ExprsVerifier.java       |  2 +-
 .../plan/verifier/PreLogicalPlanVerifier.java   |  2 +-
 .../plan/visitor/BasicLogicalPlanVisitor.java   |  2 +-
 .../plan/visitor/ExplainLogicalPlanVisitor.java |  2 +-
 .../apache/tajo/storage/TablespaceManager.java  |  4 ++--
 .../apache/tajo/storage/compress/CodecPool.java |  2 +-
 .../tajo/storage/HashShuffleAppender.java       |  2 +-
 .../objectweb/asm/util/CheckMethodAdapter.java  |  2 +-
 72 files changed, 150 insertions(+), 147 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/CHANGES
----------------------------------------------------------------------
diff --git a/CHANGES b/CHANGES
index b55ed83..716964b 100644
--- a/CHANGES
+++ b/CHANGES
@@ -44,6 +44,9 @@ Release 0.12.0 - unreleased
 
   SUB TASKS
 
+    TAJO-1909: Eliminate remained explicit diamond expressions.
+    (Contributed by Dongkyu Hwangbo, committed by hyunsik)
+
     TAJO-1844: Eliminate explicit diamond expressions. 
     (Contributed by Dongkyu Hwangbo, committed by hyunsik)
 

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-catalog/tajo-catalog-drivers/tajo-hive/src/main/java/org/apache/tajo/catalog/store/HiveCatalogStore.java
----------------------------------------------------------------------
diff --git 
a/tajo-catalog/tajo-catalog-drivers/tajo-hive/src/main/java/org/apache/tajo/catalog/store/HiveCatalogStore.java
 
b/tajo-catalog/tajo-catalog-drivers/tajo-hive/src/main/java/org/apache/tajo/catalog/store/HiveCatalogStore.java
index 8a370b9..f4e21dd 100644
--- 
a/tajo-catalog/tajo-catalog-drivers/tajo-hive/src/main/java/org/apache/tajo/catalog/store/HiveCatalogStore.java
+++ 
b/tajo-catalog/tajo-catalog-drivers/tajo-hive/src/main/java/org/apache/tajo/catalog/store/HiveCatalogStore.java
@@ -353,7 +353,7 @@ public class HiveCatalogStore extends CatalogConstants 
implements CatalogStore {
           databaseName,
           "",
           defaultTableSpaceUri + "/" + databaseName,
-          new HashMap<String, String>());
+              new HashMap<>());
       client = clientPool.getClient();
       client.getHiveClient().createDatabase(database);
     } catch (AlreadyExistsException e) {
@@ -439,7 +439,7 @@ public class HiveCatalogStore extends CatalogConstants 
implements CatalogStore {
 
       StorageDescriptor sd = new StorageDescriptor();
       sd.setSerdeInfo(new SerDeInfo());
-      sd.getSerdeInfo().setParameters(new HashMap<String, String>());
+      sd.getSerdeInfo().setParameters(new HashMap<>());
       sd.getSerdeInfo().setName(table.getTableName());
 
       // if tajo set location method, thrift client make exception as follows:
@@ -558,7 +558,7 @@ public class HiveCatalogStore extends CatalogConstants 
implements CatalogStore {
         }
       }
 
-      sd.setSortCols(new ArrayList<Order>());
+      sd.setSortCols(new ArrayList<>());
 
       table.setSd(sd);
       client.getHiveClient().createTable(table);
@@ -968,7 +968,7 @@ public class HiveCatalogStore extends CatalogConstants 
implements CatalogStore {
 
       if (!(filters[i] instanceof IsNullPredicate)) {
         visitor.setColumn(target);
-        visitor.visit(null, new Stack<Expr>(), filters[i]);
+        visitor.visit(null, new Stack<>(), filters[i]);
         result = visitor.getResult();
 
         // If visitor build filter successfully, add filter to be used for 
executing hive api.

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-catalog/tajo-catalog-drivers/tajo-hive/src/test/java/org/apache/tajo/catalog/store/TestHiveCatalogStore.java
----------------------------------------------------------------------
diff --git 
a/tajo-catalog/tajo-catalog-drivers/tajo-hive/src/test/java/org/apache/tajo/catalog/store/TestHiveCatalogStore.java
 
b/tajo-catalog/tajo-catalog-drivers/tajo-hive/src/test/java/org/apache/tajo/catalog/store/TestHiveCatalogStore.java
index 3c2c6c1..43de047 100644
--- 
a/tajo-catalog/tajo-catalog-drivers/tajo-hive/src/test/java/org/apache/tajo/catalog/store/TestHiveCatalogStore.java
+++ 
b/tajo-catalog/tajo-catalog-drivers/tajo-hive/src/test/java/org/apache/tajo/catalog/store/TestHiveCatalogStore.java
@@ -423,7 +423,7 @@ public class TestHiveCatalogStore {
       Path path = new Path(uri.getPath(), partitionName);
       builder.setPath(path.toString());
 
-      List<PartitionKeyProto> partitionKeyList = new 
ArrayList<PartitionKeyProto>();
+      List<PartitionKeyProto> partitionKeyList = new ArrayList<>();
       String[] split = partitionName.split("/");
       for(int i = 0; i < split.length; i++) {
         String[] eachPartitionName = split[i].split("=");

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-catalog/tajo-catalog-server/src/main/java/org/apache/tajo/catalog/store/AbstractDBStore.java
----------------------------------------------------------------------
diff --git 
a/tajo-catalog/tajo-catalog-server/src/main/java/org/apache/tajo/catalog/store/AbstractDBStore.java
 
b/tajo-catalog/tajo-catalog-server/src/main/java/org/apache/tajo/catalog/store/AbstractDBStore.java
index c808a50..176f569 100644
--- 
a/tajo-catalog/tajo-catalog-server/src/main/java/org/apache/tajo/catalog/store/AbstractDBStore.java
+++ 
b/tajo-catalog/tajo-catalog-server/src/main/java/org/apache/tajo/catalog/store/AbstractDBStore.java
@@ -2434,7 +2434,7 @@ public abstract class AbstractDBStore extends 
CatalogConstants implements Catalo
 
         visitor.setColumn(target);
         visitor.setTableAlias(tableAlias);
-        visitor.visit(null, new Stack<Expr>(), filters[i]);
+        visitor.visit(null, new Stack<>(), filters[i]);
 
         sb.append("\n   JOIN 
").append(CatalogConstants.TB_PARTTION_KEYS).append(" ").append(tableAlias)
           .append(" ON T1.").append(CatalogConstants.COL_TABLES_PK).append("=")
@@ -2461,7 +2461,7 @@ public abstract class AbstractDBStore extends 
CatalogConstants implements Catalo
       tableAlias = "T1";
       visitor.setColumn(target);
       visitor.setTableAlias(tableAlias);
-      visitor.visit(null, new Stack<Expr>(), filters[0]);
+      visitor.visit(null, new Stack<>(), filters[0]);
 
       sb.append("\n   WHERE 
T1.").append(CatalogConstants.COL_TABLES_PK).append(" = ? AND ");
       sb.append(visitor.getResult())

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-common/src/main/java/org/apache/tajo/common/type/TajoTypeUtil.java
----------------------------------------------------------------------
diff --git 
a/tajo-common/src/main/java/org/apache/tajo/common/type/TajoTypeUtil.java 
b/tajo-common/src/main/java/org/apache/tajo/common/type/TajoTypeUtil.java
index c4bfec4..a70218d 100644
--- a/tajo-common/src/main/java/org/apache/tajo/common/type/TajoTypeUtil.java
+++ b/tajo-common/src/main/java/org/apache/tajo/common/type/TajoTypeUtil.java
@@ -27,7 +27,7 @@ import java.util.ArrayList;
 import java.util.List;
 
 public class TajoTypeUtil {
-  private static List<Datum[]> typeInfos = new ArrayList<Datum[]>();
+  private static List<Datum[]> typeInfos = new ArrayList<>();
 
   public static List<Datum[]> getTypeInfos() {
     synchronized (typeInfos) {

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-common/src/main/java/org/apache/tajo/datum/IntervalDatum.java
----------------------------------------------------------------------
diff --git a/tajo-common/src/main/java/org/apache/tajo/datum/IntervalDatum.java 
b/tajo-common/src/main/java/org/apache/tajo/datum/IntervalDatum.java
index d3cb6c7..e797b87 100644
--- a/tajo-common/src/main/java/org/apache/tajo/datum/IntervalDatum.java
+++ b/tajo-common/src/main/java/org/apache/tajo/datum/IntervalDatum.java
@@ -37,7 +37,7 @@ public class IntervalDatum extends Datum {
   static enum DATE_UNIT {
     CENTURY, DECADE, YEAR, MONTH, DAY, HOUR, MINUTE, SECOND, MICROSEC, 
MILLISEC, TIMEZONE,
   }
-  static Map<String, DATE_UNIT> DATE_FORMAT_LITERAL = new HashMap<String, 
DATE_UNIT>();
+  static Map<String, DATE_UNIT> DATE_FORMAT_LITERAL = new HashMap<>();
   static {
     Object[][] dateFormatLiterals = new Object[][]{
         {DATE_UNIT.CENTURY, "c,cent,centuries,century"},

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-common/src/main/java/org/apache/tajo/util/BytesUtils.java
----------------------------------------------------------------------
diff --git a/tajo-common/src/main/java/org/apache/tajo/util/BytesUtils.java 
b/tajo-common/src/main/java/org/apache/tajo/util/BytesUtils.java
index 5df924b..812aa4b 100644
--- a/tajo-common/src/main/java/org/apache/tajo/util/BytesUtils.java
+++ b/tajo-common/src/main/java/org/apache/tajo/util/BytesUtils.java
@@ -202,7 +202,7 @@ public class BytesUtils {
   }
   
   public static byte[][] splitTrivial(byte[] value, byte delimiter) {
-    List<byte[]> split = new ArrayList<byte[]>();
+    List<byte[]> split = new ArrayList<>();
     int prev = 0;
     for (int i = 0; i < value.length; i++) {
       if (value[i] == delimiter) {

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-common/src/main/java/org/apache/tajo/util/ClassUtil.java
----------------------------------------------------------------------
diff --git a/tajo-common/src/main/java/org/apache/tajo/util/ClassUtil.java 
b/tajo-common/src/main/java/org/apache/tajo/util/ClassUtil.java
index 3865ee9..c93b751 100644
--- a/tajo-common/src/main/java/org/apache/tajo/util/ClassUtil.java
+++ b/tajo-common/src/main/java/org/apache/tajo/util/ClassUtil.java
@@ -39,7 +39,7 @@ public abstract class ClassUtil {
   }
 
   public static Set<Class> findClasses(@Nullable Class targetClass, String 
packageFilter, Predicate predicate) {
-    Set<Class> classSet = new HashSet<Class>();
+    Set<Class> classSet = new HashSet<>();
 
     String classpath = System.getProperty("java.class.path");
     String[] paths = classpath.split(System.getProperty("path.separator"));

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-common/src/main/java/org/apache/tajo/util/KeyValueSet.java
----------------------------------------------------------------------
diff --git a/tajo-common/src/main/java/org/apache/tajo/util/KeyValueSet.java 
b/tajo-common/src/main/java/org/apache/tajo/util/KeyValueSet.java
index 404606d..a275225 100644
--- a/tajo-common/src/main/java/org/apache/tajo/util/KeyValueSet.java
+++ b/tajo-common/src/main/java/org/apache/tajo/util/KeyValueSet.java
@@ -269,7 +269,7 @@ public class KeyValueSet implements 
ProtoObject<KeyValueSetProto>, Cloneable, Gs
        @Override
   public Object clone() throws CloneNotSupportedException {    
     KeyValueSet keyValueSet = (KeyValueSet) super.clone();
-    keyValueSet.keyVals = keyVals != null ? new HashMap<String, 
String>(keyVals) : null;
+    keyValueSet.keyVals = keyVals != null ? new HashMap<>(keyVals) : null;
     return keyValueSet;
        }
        

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-common/src/main/java/org/apache/tajo/util/ReflectionUtil.java
----------------------------------------------------------------------
diff --git a/tajo-common/src/main/java/org/apache/tajo/util/ReflectionUtil.java 
b/tajo-common/src/main/java/org/apache/tajo/util/ReflectionUtil.java
index 5a712c0..f425326 100644
--- a/tajo-common/src/main/java/org/apache/tajo/util/ReflectionUtil.java
+++ b/tajo-common/src/main/java/org/apache/tajo/util/ReflectionUtil.java
@@ -37,9 +37,9 @@ public class ReflectionUtil {
    * CONF_CONSTRUCTOR_CACHE keeps classes which have one constructor to take 
TajoConf.
    */
   private static final Map<Class<?>, Constructor<?>> EMPTY_CONSTRUCTOR_CACHE =
-      new ConcurrentHashMap<Class<?>, Constructor<?>>();
+          new ConcurrentHashMap<>();
   private static final Map<Class<?>, Constructor<?>> CONF_CONSTRUCTOR_CACHE =
-      new ConcurrentHashMap<Class<?>, Constructor<?>>();
+          new ConcurrentHashMap<>();
 
   /**
    * Initialize an instance by a given class

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-common/src/main/java/org/apache/tajo/util/ShutdownHookManager.java
----------------------------------------------------------------------
diff --git 
a/tajo-common/src/main/java/org/apache/tajo/util/ShutdownHookManager.java 
b/tajo-common/src/main/java/org/apache/tajo/util/ShutdownHookManager.java
index 3ec535f..bac0aec 100644
--- a/tajo-common/src/main/java/org/apache/tajo/util/ShutdownHookManager.java
+++ b/tajo-common/src/main/java/org/apache/tajo/util/ShutdownHookManager.java
@@ -117,7 +117,7 @@ public class ShutdownHookManager {
   List<Runnable> getShutdownHooksInOrder() {
     List<HookEntry> list;
     synchronized (MGR.hooks) {
-      list = new ArrayList<HookEntry>(MGR.hooks);
+      list = new ArrayList<>(MGR.hooks);
     }
     Collections.sort(list, new Comparator<HookEntry>() {
 
@@ -127,7 +127,7 @@ public class ShutdownHookManager {
         return o2.priority - o1.priority;
       }
     });
-    List<Runnable> ordered = new ArrayList<Runnable>();
+    List<Runnable> ordered = new ArrayList<>();
     for (HookEntry entry: list) {
       ordered.add(entry.hook);
     }

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-common/src/main/java/org/apache/tajo/util/TUtil.java
----------------------------------------------------------------------
diff --git a/tajo-common/src/main/java/org/apache/tajo/util/TUtil.java 
b/tajo-common/src/main/java/org/apache/tajo/util/TUtil.java
index f24be61..cc6b879 100644
--- a/tajo-common/src/main/java/org/apache/tajo/util/TUtil.java
+++ b/tajo-common/src/main/java/org/apache/tajo/util/TUtil.java
@@ -123,47 +123,47 @@ public class TUtil {
   }
 
   public static <T> Set<T> newHashSet() {
-    return new HashSet<T>();
+    return new HashSet<>();
   }
 
   public static <T> Set<T> newHashSet(T ...items) {
-    return new HashSet<T>(Arrays.asList(items));
+    return new HashSet<>(Arrays.asList(items));
   }
 
   public static <K,V> Map<K,V> newHashMap() {
-    return new HashMap<K, V>();
+    return new HashMap<>();
   }
 
   public static <K,V> Map<K,V> newHashMap(Map<K,V> map) {
-    return new HashMap<K, V>(map);
+    return new HashMap<>(map);
   }
 
   public static <K, V> Map<K,V> newHashMap(K k, V v) {
-    HashMap<K, V> newMap = new HashMap<K, V>();
+    HashMap<K, V> newMap = new HashMap<>();
     newMap.put(k, v);
     return newMap;
   }
 
   public static <K,V> Map<K,V> newLinkedHashMap() {
-    return new LinkedHashMap<K, V>();
+    return new LinkedHashMap<>();
   }
 
   public static <K, V> Map<K,V> newLinkedHashMap(K k, V v) {
-    HashMap<K, V> newMap = new LinkedHashMap<K, V>();
+    HashMap<K, V> newMap = new LinkedHashMap<>();
     newMap.put(k, v);
     return newMap;
   }
 
   public static <K,V> Map<K,V> newConcurrentHashMap() {
-    return new ConcurrentHashMap<K, V>();
+    return new ConcurrentHashMap<>();
   }
 
   public static <T> List<T> newList() {
-    return new ArrayList<T>();
+    return new ArrayList<>();
   }
 
   public static <T> List<T> newList(T...items) {
-    List<T> list = new ArrayList<T>();
+    List<T> list = new ArrayList<>();
     for (T t : items) {
       list.add(t);
     }
@@ -172,7 +172,7 @@ public class TUtil {
   }
 
   public static <T> List<T> newList(Collection<T> items) {
-    List<T> list = new ArrayList<T>();
+    List<T> list = new ArrayList<>();
     for (T t : items) {
       list.add(t);
     }

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-common/src/test/java/org/apache/tajo/util/graph/TestSimpleDirectedGraph.java
----------------------------------------------------------------------
diff --git 
a/tajo-common/src/test/java/org/apache/tajo/util/graph/TestSimpleDirectedGraph.java
 
b/tajo-common/src/test/java/org/apache/tajo/util/graph/TestSimpleDirectedGraph.java
index 676d39f..2f3a373 100644
--- 
a/tajo-common/src/test/java/org/apache/tajo/util/graph/TestSimpleDirectedGraph.java
+++ 
b/tajo-common/src/test/java/org/apache/tajo/util/graph/TestSimpleDirectedGraph.java
@@ -35,7 +35,7 @@ public class TestSimpleDirectedGraph {
 
   @Test
   public final void test() {
-    SimpleDirectedGraph<String, Integer> graph = new 
SimpleDirectedGraph<String, Integer>();
+    SimpleDirectedGraph<String, Integer> graph = new SimpleDirectedGraph<>();
 
     //     root
     //     /  \

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-common/src/test/java/org/apache/tajo/util/graph/TestSimpleUndirectedGraph.java
----------------------------------------------------------------------
diff --git 
a/tajo-common/src/test/java/org/apache/tajo/util/graph/TestSimpleUndirectedGraph.java
 
b/tajo-common/src/test/java/org/apache/tajo/util/graph/TestSimpleUndirectedGraph.java
index 6fdb138..1b2ff2e 100644
--- 
a/tajo-common/src/test/java/org/apache/tajo/util/graph/TestSimpleUndirectedGraph.java
+++ 
b/tajo-common/src/test/java/org/apache/tajo/util/graph/TestSimpleUndirectedGraph.java
@@ -31,7 +31,7 @@ public class TestSimpleUndirectedGraph {
 
   @Test
   public final void test() {
-    UndirectedGraph<String, Integer> graph = new SimpleUndirectedGraph<String, 
Integer>();
+    UndirectedGraph<String, Integer> graph = new SimpleUndirectedGraph<>();
 
     //     root
     //     /  \

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-common/src/test/java/org/apache/tajo/validation/TestValidators.java
----------------------------------------------------------------------
diff --git 
a/tajo-common/src/test/java/org/apache/tajo/validation/TestValidators.java 
b/tajo-common/src/test/java/org/apache/tajo/validation/TestValidators.java
index 92e016a..f2e4cdd 100644
--- a/tajo-common/src/test/java/org/apache/tajo/validation/TestValidators.java
+++ b/tajo-common/src/test/java/org/apache/tajo/validation/TestValidators.java
@@ -101,11 +101,11 @@ public class TestValidators {
   }
   
   private <T extends Validator> Matcher<? super ConstraintViolation> 
hasAClass(Matcher<Class<T>> matcher) {
-    return new ValidatorClazzMatcher<T>(matcher);
+    return new ValidatorClazzMatcher<>(matcher);
   }
   
   private <T> Matcher<Iterable<? extends T>> hasItem(Matcher<? extends T> 
matcher) {
-    return new CollectionMatcher<T>(matcher);
+    return new CollectionMatcher<>(matcher);
   }
   
   @Test

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core-tests/src/test/java/org/apache/tajo/engine/planner/TestEvalNodeToExprConverter.java
----------------------------------------------------------------------
diff --git 
a/tajo-core-tests/src/test/java/org/apache/tajo/engine/planner/TestEvalNodeToExprConverter.java
 
b/tajo-core-tests/src/test/java/org/apache/tajo/engine/planner/TestEvalNodeToExprConverter.java
index 2baa79a..018fa0e 100644
--- 
a/tajo-core-tests/src/test/java/org/apache/tajo/engine/planner/TestEvalNodeToExprConverter.java
+++ 
b/tajo-core-tests/src/test/java/org/apache/tajo/engine/planner/TestEvalNodeToExprConverter.java
@@ -126,7 +126,7 @@ public class TestEvalNodeToExprConverter {
     ScanNode scanNode = PlannerUtil.findTopNode(node, NodeType.SCAN);
 
     EvalNodeToExprConverter convertor = new 
EvalNodeToExprConverter(scanNode.getTableName());
-    convertor.visit(null, scanNode.getQual(), new Stack<EvalNode>());
+    convertor.visit(null, scanNode.getQual(), new Stack<>());
 
     Expr resultExpr = convertor.getResult();
 
@@ -156,7 +156,7 @@ public class TestEvalNodeToExprConverter {
     ScanNode scanNode = PlannerUtil.findTopNode(node, NodeType.SCAN);
 
     EvalNodeToExprConverter convertor = new 
EvalNodeToExprConverter(scanNode.getTableName());
-    convertor.visit(null, scanNode.getQual(), new Stack<EvalNode>());
+    convertor.visit(null, scanNode.getQual(), new Stack<>());
 
     Expr resultExpr = convertor.getResult();
     BinaryOperator equals = AlgebraicUtil.findTopExpr(resultExpr, 
OpType.Equals);
@@ -185,7 +185,7 @@ public class TestEvalNodeToExprConverter {
     ScanNode scanNode = PlannerUtil.findTopNode(node, NodeType.SCAN);
 
     EvalNodeToExprConverter convertor = new 
EvalNodeToExprConverter(scanNode.getTableName());
-    convertor.visit(null, scanNode.getQual(), new Stack<EvalNode>());
+    convertor.visit(null, scanNode.getQual(), new Stack<>());
 
     Expr resultExpr = convertor.getResult();
 
@@ -243,7 +243,7 @@ public class TestEvalNodeToExprConverter {
     ScanNode scanNode = PlannerUtil.findTopNode(node, NodeType.SCAN);
 
     EvalNodeToExprConverter convertor = new 
EvalNodeToExprConverter(scanNode.getTableName());
-    convertor.visit(null, scanNode.getQual(), new Stack<EvalNode>());
+    convertor.visit(null, scanNode.getQual(), new Stack<>());
 
     Expr resultExpr = convertor.getResult();
 
@@ -298,7 +298,7 @@ public class TestEvalNodeToExprConverter {
     ScanNode scanNode = PlannerUtil.findTopNode(node, NodeType.SCAN);
 
     EvalNodeToExprConverter convertor = new 
EvalNodeToExprConverter(scanNode.getTableName());
-    convertor.visit(null, scanNode.getQual(), new Stack<EvalNode>());
+    convertor.visit(null, scanNode.getQual(), new Stack<>());
 
     Expr resultExpr = convertor.getResult();
 
@@ -353,7 +353,7 @@ public class TestEvalNodeToExprConverter {
     ScanNode scanNode = PlannerUtil.findTopNode(node, NodeType.SCAN);
 
     EvalNodeToExprConverter convertor = new 
EvalNodeToExprConverter(scanNode.getTableName());
-    convertor.visit(null, scanNode.getQual(), new Stack<EvalNode>());
+    convertor.visit(null, scanNode.getQual(), new Stack<>());
 
     Expr resultExpr = convertor.getResult();
 

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core-tests/src/test/java/org/apache/tajo/engine/planner/TestLogicalPlanner.java
----------------------------------------------------------------------
diff --git 
a/tajo-core-tests/src/test/java/org/apache/tajo/engine/planner/TestLogicalPlanner.java
 
b/tajo-core-tests/src/test/java/org/apache/tajo/engine/planner/TestLogicalPlanner.java
index 3e99143..0f09c0c 100644
--- 
a/tajo-core-tests/src/test/java/org/apache/tajo/engine/planner/TestLogicalPlanner.java
+++ 
b/tajo-core-tests/src/test/java/org/apache/tajo/engine/planner/TestLogicalPlanner.java
@@ -1036,7 +1036,7 @@ public class TestLogicalPlanner {
     testGenerateCuboids[1] = new Column("col2", Type.INT8);
     testGenerateCuboids[2] = new Column("col3", Type.FLOAT4);
 
-    testGenerateCuboidsResult.add(new HashSet<Column>());
+    testGenerateCuboidsResult.add(new HashSet<>());
     testGenerateCuboidsResult.add(Sets.newHashSet(testGenerateCuboids[0]));
     testGenerateCuboidsResult.add(Sets.newHashSet(testGenerateCuboids[1]));
     testGenerateCuboidsResult.add(Sets.newHashSet(testGenerateCuboids[2]));
@@ -1051,7 +1051,7 @@ public class TestLogicalPlanner {
 
     testCubeByCuboids[0] = new Column("employee.name", Type.TEXT);
     testCubeByCuboids[1] = new Column("employee.empid", Type.INT4);
-    testCubeByResult.add(new HashSet<Column>());
+    testCubeByResult.add(new HashSet<>());
     testCubeByResult.add(Sets.newHashSet(testCubeByCuboids[0]));
     testCubeByResult.add(Sets.newHashSet(testCubeByCuboids[1]));
     testCubeByResult.add(Sets.newHashSet(testCubeByCuboids[0],

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core-tests/src/test/java/org/apache/tajo/master/TestRepartitioner.java
----------------------------------------------------------------------
diff --git 
a/tajo-core-tests/src/test/java/org/apache/tajo/master/TestRepartitioner.java 
b/tajo-core-tests/src/test/java/org/apache/tajo/master/TestRepartitioner.java
index c1461b0..bb83e9c 100644
--- 
a/tajo-core-tests/src/test/java/org/apache/tajo/master/TestRepartitioner.java
+++ 
b/tajo-core-tests/src/test/java/org/apache/tajo/master/TestRepartitioner.java
@@ -56,7 +56,7 @@ public class TestRepartitioner {
 
     Map<Integer, List<IntermediateEntry>> intermediateEntries = new 
HashMap<>();
     for (int i = 0; i < numPartition; i++) {
-      intermediateEntries.put(i, new ArrayList<IntermediateEntry>());
+      intermediateEntries.put(i, new ArrayList<>());
     }
     for (int i = 0; i < 1000; i++) {
       int partitionId = i % numPartition;

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core-tests/src/test/java/org/apache/tajo/master/scheduler/TestSimpleScheduler.java
----------------------------------------------------------------------
diff --git 
a/tajo-core-tests/src/test/java/org/apache/tajo/master/scheduler/TestSimpleScheduler.java
 
b/tajo-core-tests/src/test/java/org/apache/tajo/master/scheduler/TestSimpleScheduler.java
index 89fdba0..b4bc110 100644
--- 
a/tajo-core-tests/src/test/java/org/apache/tajo/master/scheduler/TestSimpleScheduler.java
+++ 
b/tajo-core-tests/src/test/java/org/apache/tajo/master/scheduler/TestSimpleScheduler.java
@@ -181,7 +181,7 @@ public class TestSimpleScheduler {
     QueryId queryId = QueryIdFactory.newQueryId(System.nanoTime(), 0);
     CallFuture<NodeResourceResponse> callBack = new CallFuture<>();
     rmContext.getDispatcher().getEventHandler().handle(new 
ResourceReserveSchedulerEvent(
-        createResourceRequest(queryId, requestNum, new ArrayList<Integer>()), 
callBack));
+        createResourceRequest(queryId, requestNum, new ArrayList<>()), 
callBack));
 
     NodeResourceResponse responseProto = callBack.get();
     assertEquals(queryId, new QueryId(responseProto.getQueryId()));

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core-tests/src/test/java/org/apache/tajo/querymaster/TestKillQuery.java
----------------------------------------------------------------------
diff --git 
a/tajo-core-tests/src/test/java/org/apache/tajo/querymaster/TestKillQuery.java 
b/tajo-core-tests/src/test/java/org/apache/tajo/querymaster/TestKillQuery.java
index 5c0b11d..f907a2b 100644
--- 
a/tajo-core-tests/src/test/java/org/apache/tajo/querymaster/TestKillQuery.java
+++ 
b/tajo-core-tests/src/test/java/org/apache/tajo/querymaster/TestKillQuery.java
@@ -233,7 +233,7 @@ public class TestKillQuery {
     WorkerConnectionInfo queryMaster = new WorkerConnectionInfo("host", 28091, 
28092, 21000, 28093, 28080);
 
     TaskAttemptId attemptId = new TaskAttemptId(tid, 1);
-    taskRequest.set(attemptId, new ArrayList<CatalogProtos.FragmentProto>(),
+    taskRequest.set(attemptId, new ArrayList<>(),
         null, false, PlanProto.LogicalNodeTree.newBuilder().build(), new 
QueryContext(conf),
         null, null, queryMaster.getHostAndQMPort());
     taskRequest.setInterQuery();

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestClusterResource.java
----------------------------------------------------------------------
diff --git 
a/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestClusterResource.java
 
b/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestClusterResource.java
index 7e18c1d..42671d4 100644
--- 
a/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestClusterResource.java
+++ 
b/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestClusterResource.java
@@ -70,7 +70,7 @@ public class TestClusterResource extends QueryTestCaseBase {
   public void testGetCluster() throws Exception {
     Map<String, List<Object>> workerMap =
         restClient.target(clusterURI)
-        .request().get(new GenericType<Map<String, List<Object>>>(Map.class));
+        .request().get(new GenericType<>(Map.class));
     
     assertNotNull(workerMap);
     assertFalse(workerMap.isEmpty());

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestDatabasesResource.java
----------------------------------------------------------------------
diff --git 
a/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestDatabasesResource.java
 
b/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestDatabasesResource.java
index 59c53f1..b2afda2 100644
--- 
a/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestDatabasesResource.java
+++ 
b/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestDatabasesResource.java
@@ -75,7 +75,7 @@ public class TestDatabasesResource extends QueryTestCaseBase {
   @Test
   public void testGetAllDatabases() throws Exception {
     Map<String, Collection<String>> databaseNames = 
restClient.target(databasesURI)
-        .request().get(new GenericType<Map<String, 
Collection<String>>>(Map.class));
+        .request().get(new GenericType<>(Map.class));
     
     assertNotNull(databaseNames);
     assertFalse(databaseNames.isEmpty());
@@ -100,7 +100,7 @@ public class TestDatabasesResource extends 
QueryTestCaseBase {
     assertEquals(Status.CREATED.getStatusCode(), response.getStatus());
     
     Map<String, Collection<String>> databaseNames = 
restClient.target(databasesURI)
-        .request().get(new GenericType<Map<String, 
Collection<String>>>(Map.class));
+        .request().get(new GenericType<>(Map.class));
     
     assertNotNull(databaseNames);
     assertFalse(databaseNames.isEmpty());
@@ -127,7 +127,7 @@ public class TestDatabasesResource extends 
QueryTestCaseBase {
     DatabaseInfoResponse response =
         restClient.target(databasesURI).path("/{databaseName}")
         .resolveTemplate("databaseName", TajoConstants.DEFAULT_DATABASE_NAME)
-        .request().get(new 
GenericType<DatabaseInfoResponse>(DatabaseInfoResponse.class));
+        .request().get(new GenericType<>(DatabaseInfoResponse.class));
     
     assertNotNull(response);
     assertEquals(TajoConstants.DEFAULT_DATABASE_NAME, response.getName());
@@ -159,7 +159,7 @@ public class TestDatabasesResource extends 
QueryTestCaseBase {
     assertEquals(Status.CREATED.getStatusCode(), response.getStatus());
     
     Map<String, Collection<String>> databaseNames = 
restClient.target(databasesURI)
-        .request().get(new GenericType<Map<String, 
Collection<String>>>(Map.class));
+        .request().get(new GenericType<>(Map.class));
     
     assertNotNull(databaseNames);
     assertFalse(databaseNames.isEmpty());

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestFunctionsResource.java
----------------------------------------------------------------------
diff --git 
a/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestFunctionsResource.java
 
b/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestFunctionsResource.java
index 7c7aeae..0d704d9 100644
--- 
a/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestFunctionsResource.java
+++ 
b/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestFunctionsResource.java
@@ -70,7 +70,7 @@ public class TestFunctionsResource extends QueryTestCaseBase {
   public void testGetAllFunctions() throws Exception {
     List<FunctionSignature> functionSignatures =
         restClient.target(functionsURI)
-        .request().get(new GenericType<List<FunctionSignature>>(List.class));
+        .request().get(new GenericType<>(List.class));
     
     assertNotNull(functionSignatures);
     assertTrue(functionSignatures.size() > 0);

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestQueryResource.java
----------------------------------------------------------------------
diff --git 
a/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestQueryResource.java
 
b/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestQueryResource.java
index 210d38d..420a0d6 100644
--- 
a/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestQueryResource.java
+++ 
b/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestQueryResource.java
@@ -108,7 +108,7 @@ public class TestQueryResource extends QueryTestCaseBase {
     GetSubmitQueryResponse response = restClient.target(queriesURI)
         .request().header(tajoSessionIdHeaderName, sessionId)
         .post(Entity.entity(queryRequest, MediaType.APPLICATION_JSON),
-            new 
GenericType<GetSubmitQueryResponse>(GetSubmitQueryResponse.class));
+                new GenericType<>(GetSubmitQueryResponse.class));
 
     assertNotNull(response);
     assertEquals(ResultCode.OK, response.getResultCode());
@@ -121,7 +121,7 @@ public class TestQueryResource extends QueryTestCaseBase {
     assertTrue(queryId != null && !queryId.isEmpty());
     
     Map<String, List<StringMap>> queriesMap = restClient.target(queriesURI)
-        .request().get(new GenericType<Map<String, 
List<StringMap>>>(Map.class));
+        .request().get(new GenericType<>(Map.class));
     
     assertNotNull(queriesMap);
     
@@ -146,7 +146,7 @@ public class TestQueryResource extends QueryTestCaseBase {
     GetSubmitQueryResponse response = restClient.target(queriesURI)
         .request().header(tajoSessionIdHeaderName, sessionId)
         .post(Entity.entity(queryRequest, MediaType.APPLICATION_JSON),
-            new 
GenericType<GetSubmitQueryResponse>(GetSubmitQueryResponse.class));
+                new GenericType<>(GetSubmitQueryResponse.class));
 
     assertNotNull(response);
     assertEquals(ResultCode.OK, response.getResultCode());
@@ -162,7 +162,7 @@ public class TestQueryResource extends QueryTestCaseBase {
         .path("/{queryId}")
         .resolveTemplate("queryId", queryId)
         .queryParam("print", "BRIEF")
-        .request().get(new GenericType<QueryInfo>(QueryInfo.class));
+        .request().get(new GenericType<>(QueryInfo.class));
     
     assertNotNull(queryInfo);
     assertEquals(queryId, queryInfo.getQueryIdStr());
@@ -176,7 +176,7 @@ public class TestQueryResource extends QueryTestCaseBase {
     GetSubmitQueryResponse response = restClient.target(queriesURI)
       .request().header(tajoSessionIdHeaderName, sessionId)
       .post(Entity.entity(queryRequest, MediaType.APPLICATION_JSON),
-          new 
GenericType<GetSubmitQueryResponse>(GetSubmitQueryResponse.class));
+              new GenericType<>(GetSubmitQueryResponse.class));
 
     assertNotNull(response);
     assertEquals(ResultCode.OK, response.getResultCode());
@@ -191,7 +191,7 @@ public class TestQueryResource extends QueryTestCaseBase {
     QueryInfo queryInfo = restClient.target(queriesURI)
       .path("/{queryId}")
       .resolveTemplate("queryId", queryId)
-      .request().get(new GenericType<QueryInfo>(QueryInfo.class));
+      .request().get(new GenericType<>(QueryInfo.class));
 
     assertNotNull(queryInfo);
     assertEquals(queryId, queryInfo.getQueryIdStr());

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestQueryResultResource.java
----------------------------------------------------------------------
diff --git 
a/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestQueryResultResource.java
 
b/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestQueryResultResource.java
index 7762b05..275e255 100644
--- 
a/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestQueryResultResource.java
+++ 
b/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestQueryResultResource.java
@@ -116,7 +116,7 @@ public class TestQueryResultResource extends 
QueryTestCaseBase {
     GetSubmitQueryResponse response = restClient.target(queriesURI)
         .request().header(tajoSessionIdHeaderName, sessionId)
         .post(Entity.entity(request, MediaType.APPLICATION_JSON),
-                                       new 
GenericType<GetSubmitQueryResponse>(GetSubmitQueryResponse.class));
+                new GenericType<>(GetSubmitQueryResponse.class));
 
     assertNotNull(response);
     assertEquals(ResultCode.OK, response.getResultCode());
@@ -138,7 +138,7 @@ public class TestQueryResultResource extends 
QueryTestCaseBase {
 
     GetQueryResultDataResponse response = restClient.target(queryResultURI)
         .request().header(tajoSessionIdHeaderName, sessionId)
-        .get(new 
GenericType<GetQueryResultDataResponse>(GetQueryResultDataResponse.class));
+        .get(new GenericType<>(GetQueryResultDataResponse.class));
 
     assertNotNull(response);
     assertNotNull(response.getResultCode());
@@ -172,7 +172,7 @@ public class TestQueryResultResource extends 
QueryTestCaseBase {
 
     GetQueryResultDataResponse response = restClient.target(queryResultURI)
         .request().header(tajoSessionIdHeaderName, sessionId)
-        .get(new 
GenericType<GetQueryResultDataResponse>(GetQueryResultDataResponse.class));
+        .get(new GenericType<>(GetQueryResultDataResponse.class));
 
     assertNotNull(response);
     assertNotNull(response.getResultCode());
@@ -234,7 +234,7 @@ public class TestQueryResultResource extends 
QueryTestCaseBase {
 
     GetQueryResultDataResponse response = restClient.target(queryResultURI)
         .request().header(tajoSessionIdHeaderName, sessionId)
-        .get(new 
GenericType<GetQueryResultDataResponse>(GetQueryResultDataResponse.class));
+        .get(new GenericType<>(GetQueryResultDataResponse.class));
 
     assertNotNull(response);
     assertNotNull(response.getResultCode());

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestSessionsResource.java
----------------------------------------------------------------------
diff --git 
a/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestSessionsResource.java
 
b/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestSessionsResource.java
index 99a6d62..f939db2 100644
--- 
a/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestSessionsResource.java
+++ 
b/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestSessionsResource.java
@@ -166,7 +166,7 @@ public class TestSessionsResource extends QueryTestCaseBase 
{
 
     Map<String, Map<String, String>> variablesMap = 
restClient.target(sessionsURI)
         .path("/{session-id}/variables").resolveTemplate("session-id", 
response.getId())
-        .request().get(new GenericType<Map<String, Map<String, 
String>>>(Map.class));
+        .request().get(new GenericType<>(Map.class));
 
     assertNotNull(variablesMap);
     assertTrue(variablesMap.containsKey("variables"));
@@ -209,7 +209,7 @@ public class TestSessionsResource extends QueryTestCaseBase 
{
     
     Map<String, Map<String, String>> retrievedVariables = 
restClient.target(sessionsURI)
         .path("/{session-id}/variables").resolveTemplate("session-id", 
response.getId())
-        .request().get(new GenericType<Map<String, Map<String, 
String>>>(Map.class));
+        .request().get(new GenericType<>(Map.class));
     
     assertNotNull(retrievedVariables);
     assertFalse(retrievedVariables.isEmpty());
@@ -247,7 +247,7 @@ public class TestSessionsResource extends QueryTestCaseBase 
{
     
     Map<String, Map<String, String>> retrievedVariables = 
restClient.target(sessionsURI)
         .path("/{session-id}/variables").resolveTemplate("session-id", 
response.getId())
-        .request().get(new GenericType<Map<String, Map<String, 
String>>>(Map.class));
+        .request().get(new GenericType<>(Map.class));
     
     assertNotNull(retrievedVariables);
     assertFalse(retrievedVariables.isEmpty());

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestTablesResource.java
----------------------------------------------------------------------
diff --git 
a/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestTablesResource.java
 
b/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestTablesResource.java
index aa8a696..423e80b 100644
--- 
a/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestTablesResource.java
+++ 
b/tajo-core-tests/src/test/java/org/apache/tajo/ws/rs/resources/TestTablesResource.java
@@ -112,7 +112,7 @@ public class TestTablesResource extends QueryTestCaseBase {
                GetSubmitQueryResponse response = restClient.target(queriesURI)
                        .request().header(tajoSessionIdHeaderName, sessionId)
                        .post(Entity.entity(queryRequest, 
MediaType.APPLICATION_JSON),
-                               new 
GenericType<GetSubmitQueryResponse>(GetSubmitQueryResponse.class));
+                    new GenericType<>(GetSubmitQueryResponse.class));
 
                assertNotNull(response);
                assertEquals(ResultCode.OK, response.getResultCode());
@@ -126,7 +126,7 @@ public class TestTablesResource extends QueryTestCaseBase {
                createNewTableForTestCreateTable(tableName, sessionId);
 
     Map<String, Collection<String>> tables = restClient.target(tablesURI)
-        .request().get(new GenericType<Map<String, 
Collection<String>>>(Map.class));
+        .request().get(new GenericType<>(Map.class));
 
     List<String> tableNames = (List<String>)tables.get("tables");
     assertNotNull(tableNames);
@@ -152,7 +152,7 @@ public class TestTablesResource extends QueryTestCaseBase {
     
     TableDesc selectedTable = restClient.target(tablesURI)
         .path("/{tableName}").resolveTemplate("tableName", tableName)
-        .request().get(new GenericType<TableDesc>(TableDesc.class));
+        .request().get(new GenericType<>(TableDesc.class));
     
     assertNotNull(selectedTable);
     assertTrue(StringUtils.equalsIgnoreCase(tableName, 
CatalogUtil.extractSimpleName(selectedTable.getName())));
@@ -177,7 +177,7 @@ public class TestTablesResource extends QueryTestCaseBase {
     
     TableDesc selectedTable = restClient.target(tablesURI)
         .path("/{tableName}").resolveTemplate("tableName", tableName)
-        .request().get(new GenericType<TableDesc>(TableDesc.class));
+        .request().get(new GenericType<>(TableDesc.class));
     
     assertNotNull(selectedTable);
     assertTrue(StringUtils.equalsIgnoreCase(tableName, 
CatalogUtil.extractSimpleName(selectedTable.getName())));

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core/src/main/java/org/apache/tajo/engine/codegen/EvalCodeGenContext.java
----------------------------------------------------------------------
diff --git 
a/tajo-core/src/main/java/org/apache/tajo/engine/codegen/EvalCodeGenContext.java
 
b/tajo-core/src/main/java/org/apache/tajo/engine/codegen/EvalCodeGenContext.java
index 32fb562..ca3466b 100644
--- 
a/tajo-core/src/main/java/org/apache/tajo/engine/codegen/EvalCodeGenContext.java
+++ 
b/tajo-core/src/main/java/org/apache/tajo/engine/codegen/EvalCodeGenContext.java
@@ -71,7 +71,7 @@ public class EvalCodeGenContext extends TajoGeneratorAdapter {
         "L" + TajoGeneratorAdapter.getInternalName(Schema.class) + ";", null, 
null);
 
     VariablesPreBuilder builder = new VariablesPreBuilder();
-    builder.visit(this, evalNode, new Stack<EvalNode>());
+    builder.visit(this, evalNode, new Stack<>());
   }
 
   public static void emitCreateSchema(TajoGeneratorAdapter adapter, 
MethodVisitor mv, Schema schema) {

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core/src/main/java/org/apache/tajo/engine/codegen/EvalCodeGenerator.java
----------------------------------------------------------------------
diff --git 
a/tajo-core/src/main/java/org/apache/tajo/engine/codegen/EvalCodeGenerator.java 
b/tajo-core/src/main/java/org/apache/tajo/engine/codegen/EvalCodeGenerator.java
index 8b87ea9..1bf0d57 100644
--- 
a/tajo-core/src/main/java/org/apache/tajo/engine/codegen/EvalCodeGenerator.java
+++ 
b/tajo-core/src/main/java/org/apache/tajo/engine/codegen/EvalCodeGenerator.java
@@ -84,7 +84,7 @@ public class EvalCodeGenerator extends 
SimpleEvalNodeVisitor<EvalCodeGenContext>
     String className = EvalCodeGenerator.class.getPackage().getName() + 
".CompiledEval" + getAndIncrementClassSeq();
     EvalCodeGenContext context = new 
EvalCodeGenContext(TajoGeneratorAdapter.getInternalName(className),
         schema, classWriter, expr);
-    visit(context, expr, new Stack<EvalNode>());
+    visit(context, expr, new Stack<>());
     context.emitReturn();
 
     Class aClass = classLoader.defineClass(className, 
classWriter.toByteArray());

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core/src/main/java/org/apache/tajo/engine/codegen/ExecutorPreCompiler.java
----------------------------------------------------------------------
diff --git 
a/tajo-core/src/main/java/org/apache/tajo/engine/codegen/ExecutorPreCompiler.java
 
b/tajo-core/src/main/java/org/apache/tajo/engine/codegen/ExecutorPreCompiler.java
index adf83ba..f63e46f 100644
--- 
a/tajo-core/src/main/java/org/apache/tajo/engine/codegen/ExecutorPreCompiler.java
+++ 
b/tajo-core/src/main/java/org/apache/tajo/engine/codegen/ExecutorPreCompiler.java
@@ -45,14 +45,14 @@ public class ExecutorPreCompiler extends 
BasicLogicalPlanVisitor<ExecutorPreComp
   }
 
   public static void compile(CompilationContext context, LogicalNode node) 
throws TajoException {
-    instance.visit(context, null, null, node, new Stack<LogicalNode>());
+    instance.visit(context, null, null, node, new Stack<>());
     context.compiledEval = Collections.unmodifiableMap(context.compiledEval);
   }
 
   public static Map<Pair<Schema, EvalNode>, EvalNode> compile(TajoClassLoader 
classLoader, LogicalNode node)
       throws TajoException {
     CompilationContext context = new CompilationContext(classLoader);
-    instance.visit(context, null, null, node, new Stack<LogicalNode>());
+    instance.visit(context, null, null, node, new Stack<>());
     return context.compiledEval;
   }
 

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core/src/main/java/org/apache/tajo/engine/planner/PhysicalPlannerImpl.java
----------------------------------------------------------------------
diff --git 
a/tajo-core/src/main/java/org/apache/tajo/engine/planner/PhysicalPlannerImpl.java
 
b/tajo-core/src/main/java/org/apache/tajo/engine/planner/PhysicalPlannerImpl.java
index cdc21d2..52e3b89 100644
--- 
a/tajo-core/src/main/java/org/apache/tajo/engine/planner/PhysicalPlannerImpl.java
+++ 
b/tajo-core/src/main/java/org/apache/tajo/engine/planner/PhysicalPlannerImpl.java
@@ -86,7 +86,7 @@ public class PhysicalPlannerImpl implements PhysicalPlanner {
     PhysicalExec execPlan;
 
     try {
-      execPlan = createPlanRecursive(context, logicalPlan, new 
Stack<LogicalNode>());
+      execPlan = createPlanRecursive(context, logicalPlan, new Stack<>());
       if (execPlan instanceof StoreTableExec
           || execPlan instanceof RangeShuffleFileWriteExec
           || execPlan instanceof HashShuffleFileWriteExec

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core/src/main/java/org/apache/tajo/engine/planner/global/GlobalPlanner.java
----------------------------------------------------------------------
diff --git 
a/tajo-core/src/main/java/org/apache/tajo/engine/planner/global/GlobalPlanner.java
 
b/tajo-core/src/main/java/org/apache/tajo/engine/planner/global/GlobalPlanner.java
index 576c880..5f8bd11 100644
--- 
a/tajo-core/src/main/java/org/apache/tajo/engine/planner/global/GlobalPlanner.java
+++ 
b/tajo-core/src/main/java/org/apache/tajo/engine/planner/global/GlobalPlanner.java
@@ -136,7 +136,7 @@ public class GlobalPlanner {
     // Its output is a graph, where each vertex is an execution block, and 
each edge is a data channel.
     // MasterPlan contains them.
     LogicalNode lastNode = planner.visit(globalPlanContext,
-        masterPlan.getLogicalPlan(), 
masterPlan.getLogicalPlan().getRootBlock(), inputPlan, new 
Stack<LogicalNode>());
+        masterPlan.getLogicalPlan(), 
masterPlan.getLogicalPlan().getRootBlock(), inputPlan, new Stack<>());
     ExecutionBlock childExecBlock = 
globalPlanContext.execBlockMap.get(lastNode.getPID());
 
     ExecutionBlock terminalBlock;

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core/src/main/java/org/apache/tajo/engine/planner/global/ParallelExecutionQueue.java
----------------------------------------------------------------------
diff --git 
a/tajo-core/src/main/java/org/apache/tajo/engine/planner/global/ParallelExecutionQueue.java
 
b/tajo-core/src/main/java/org/apache/tajo/engine/planner/global/ParallelExecutionQueue.java
index 70397ff..23e309f 100644
--- 
a/tajo-core/src/main/java/org/apache/tajo/engine/planner/global/ParallelExecutionQueue.java
+++ 
b/tajo-core/src/main/java/org/apache/tajo/engine/planner/global/ParallelExecutionQueue.java
@@ -45,7 +45,7 @@ public class ParallelExecutionQueue implements 
ExecutionQueue, Iterable<Executio
 
   private List<Deque<ExecutionBlock>> toStacks(ExecutionBlock root) {
     List<Deque<ExecutionBlock>> stacks = new ArrayList<>();
-    toStacks(root, stacks, new ArrayList<ExecutionBlock>());
+    toStacks(root, stacks, new ArrayList<>());
     return stacks;
   }
 
@@ -58,7 +58,7 @@ public class ParallelExecutionQueue implements 
ExecutionQueue, Iterable<Executio
     } else {
       List<ExecutionBlock> children = masterPlan.getChilds(current);
       for (int i = 0; i < children.size(); i++) {
-        toStacks(children.get(i), queues, i == 0 ? stack : new 
Stack<ExecutionBlock>());
+        toStacks(children.get(i), queues, i == 0 ? stack : new Stack<>());
       }
     }
   }

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core/src/main/java/org/apache/tajo/engine/planner/physical/HashJoinExec.java
----------------------------------------------------------------------
diff --git 
a/tajo-core/src/main/java/org/apache/tajo/engine/planner/physical/HashJoinExec.java
 
b/tajo-core/src/main/java/org/apache/tajo/engine/planner/physical/HashJoinExec.java
index cca3548..e47e515 100644
--- 
a/tajo-core/src/main/java/org/apache/tajo/engine/planner/physical/HashJoinExec.java
+++ 
b/tajo-core/src/main/java/org/apache/tajo/engine/planner/physical/HashJoinExec.java
@@ -35,7 +35,7 @@ public class HashJoinExec extends 
CommonHashJoinExec<TupleList> {
   @Override
   protected TupleMap<TupleList> convert(TupleMap<TupleList> hashed, boolean 
fromCache)
       throws IOException {
-    return fromCache ? new TupleMap<TupleList>(hashed) : hashed;
+    return fromCache ? new TupleMap<>(hashed) : hashed;
   }
 
   @Override

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core/src/main/java/org/apache/tajo/engine/planner/physical/PhysicalPlanUtil.java
----------------------------------------------------------------------
diff --git 
a/tajo-core/src/main/java/org/apache/tajo/engine/planner/physical/PhysicalPlanUtil.java
 
b/tajo-core/src/main/java/org/apache/tajo/engine/planner/physical/PhysicalPlanUtil.java
index 6bd084b..0d9db1d 100644
--- 
a/tajo-core/src/main/java/org/apache/tajo/engine/planner/physical/PhysicalPlanUtil.java
+++ 
b/tajo-core/src/main/java/org/apache/tajo/engine/planner/physical/PhysicalPlanUtil.java
@@ -52,7 +52,7 @@ import java.util.concurrent.atomic.AtomicInteger;
 public class PhysicalPlanUtil {
   public static <T extends PhysicalExec> T findExecutor(PhysicalExec plan, 
Class<? extends PhysicalExec> clazz)
       throws PhysicalPlanningException {
-    return (T) new FindVisitor().visit(plan, new Stack<PhysicalExec>(), clazz);
+    return (T) new FindVisitor().visit(plan, new Stack<>(), clazz);
   }
 
   public static TupleComparator [] getComparatorsFromJoinQual(EvalNode 
joinQual, Schema leftSchema, Schema rightSchema) {

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core/src/main/java/org/apache/tajo/master/rm/TajoRMContext.java
----------------------------------------------------------------------
diff --git 
a/tajo-core/src/main/java/org/apache/tajo/master/rm/TajoRMContext.java 
b/tajo-core/src/main/java/org/apache/tajo/master/rm/TajoRMContext.java
index 9dfae7e..3078a5e 100644
--- a/tajo-core/src/main/java/org/apache/tajo/master/rm/TajoRMContext.java
+++ b/tajo-core/src/main/java/org/apache/tajo/master/rm/TajoRMContext.java
@@ -40,7 +40,7 @@ public class TajoRMContext {
   private final ConcurrentMap<Integer, NodeStatus> inactiveNodes = 
Maps.newConcurrentMap();
 
   private final Set<Integer> liveQueryMasterWorkerResources =
-      Collections.newSetFromMap(new ConcurrentHashMap<Integer, Boolean>());
+      Collections.newSetFromMap(new ConcurrentHashMap<>());
 
 
   public TajoRMContext(Dispatcher dispatcher) {

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core/src/main/java/org/apache/tajo/querymaster/DefaultTaskScheduler.java
----------------------------------------------------------------------
diff --git 
a/tajo-core/src/main/java/org/apache/tajo/querymaster/DefaultTaskScheduler.java 
b/tajo-core/src/main/java/org/apache/tajo/querymaster/DefaultTaskScheduler.java
index e3bd97d..0799fa3 100644
--- 
a/tajo-core/src/main/java/org/apache/tajo/querymaster/DefaultTaskScheduler.java
+++ 
b/tajo-core/src/main/java/org/apache/tajo/querymaster/DefaultTaskScheduler.java
@@ -369,7 +369,7 @@ public class DefaultTaskScheduler extends 
AbstractTaskScheduler {
     private final String rack;
     /** A key is disk volume, and a value is a list of tasks to be scheduled. 
*/
     private Map<Integer, LinkedHashSet<TaskAttempt>> 
unassignedTaskForEachVolume =
-        Collections.synchronizedMap(new HashMap<Integer, 
LinkedHashSet<TaskAttempt>>());
+        Collections.synchronizedMap(new HashMap<>());
     /** A value is last assigned volume id for each task runner */
     private HashMap<TaskAttemptId, Integer> lastAssignedVolumeId = 
Maps.newHashMap();
     /**
@@ -618,8 +618,8 @@ public class DefaultTaskScheduler extends 
AbstractTaskScheduler {
     // two list leafTasks and nonLeafTasks keep all tasks to be scheduled. 
Even though some task is included in
     // leafTaskHostMapping or leafTasksRackMapping, some task T will not be 
sent to a task runner
     // if the task is not included in leafTasks and nonLeafTasks.
-    private final Set<TaskAttemptId> leafTasks = 
Collections.synchronizedSet(new HashSet<TaskAttemptId>());
-    private final Set<TaskAttemptId> nonLeafTasks = 
Collections.synchronizedSet(new HashSet<TaskAttemptId>());
+    private final Set<TaskAttemptId> leafTasks = 
Collections.synchronizedSet(new HashSet<>());
+    private final Set<TaskAttemptId> nonLeafTasks = 
Collections.synchronizedSet(new HashSet<>());
     private Map<String, HostVolumeMapping> leafTaskHostMapping = 
Maps.newConcurrentMap();
     private final Map<String, HashSet<TaskAttemptId>> leafTasksRackMapping = 
Maps.newConcurrentMap();
 

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core/src/main/java/org/apache/tajo/querymaster/Repartitioner.java
----------------------------------------------------------------------
diff --git 
a/tajo-core/src/main/java/org/apache/tajo/querymaster/Repartitioner.java 
b/tajo-core/src/main/java/org/apache/tajo/querymaster/Repartitioner.java
index 4fe7718..815c44b 100644
--- a/tajo-core/src/main/java/org/apache/tajo/querymaster/Repartitioner.java
+++ b/tajo-core/src/main/java/org/apache/tajo/querymaster/Repartitioner.java
@@ -326,13 +326,13 @@ public class Repartitioner {
         if (hashEntries.containsKey(emptyPartitionId)) {
           Map<ExecutionBlockId, List<IntermediateEntry>> tbNameToInterm = 
hashEntries.get(emptyPartitionId);
           if (tbNameToInterm.containsKey(scanEbId))
-            tbNameToInterm.get(scanEbId).addAll(new 
ArrayList<IntermediateEntry>());
+            tbNameToInterm.get(scanEbId).addAll(new ArrayList<>());
           else
-            tbNameToInterm.put(scanEbId, new ArrayList<IntermediateEntry>());
+            tbNameToInterm.put(scanEbId, new ArrayList<>());
         } else {
           Map<ExecutionBlockId, List<IntermediateEntry>> tbNameToInterm =
                   new HashMap<>();
-          tbNameToInterm.put(scanEbId, new ArrayList<IntermediateEntry>());
+          tbNameToInterm.put(scanEbId, new ArrayList<>());
           hashEntries.put(emptyPartitionId, tbNameToInterm);
         }
       }

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core/src/main/java/org/apache/tajo/util/metrics/reporter/TajoMetricsReporter.java
----------------------------------------------------------------------
diff --git 
a/tajo-core/src/main/java/org/apache/tajo/util/metrics/reporter/TajoMetricsReporter.java
 
b/tajo-core/src/main/java/org/apache/tajo/util/metrics/reporter/TajoMetricsReporter.java
index d6e27d3..be46bdf 100644
--- 
a/tajo-core/src/main/java/org/apache/tajo/util/metrics/reporter/TajoMetricsReporter.java
+++ 
b/tajo-core/src/main/java/org/apache/tajo/util/metrics/reporter/TajoMetricsReporter.java
@@ -58,7 +58,7 @@ public abstract class TajoMetricsReporter {
         groupName = "";
         itemName = key;
         if(!metricsGroup.containsKey(groupName)) {
-          metricsGroup.put(groupName, new HashMap<String, T>());
+          metricsGroup.put(groupName, new HashMap<>());
         }
         metricsGroup.get(groupName).put(itemName, entry.getValue());
         continue;

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core/src/main/java/org/apache/tajo/worker/FetchImpl.java
----------------------------------------------------------------------
diff --git a/tajo-core/src/main/java/org/apache/tajo/worker/FetchImpl.java 
b/tajo-core/src/main/java/org/apache/tajo/worker/FetchImpl.java
index 3fa9d11..7d2033c 100644
--- a/tajo-core/src/main/java/org/apache/tajo/worker/FetchImpl.java
+++ b/tajo-core/src/main/java/org/apache/tajo/worker/FetchImpl.java
@@ -79,13 +79,13 @@ public class FetchImpl implements ProtoObject<FetchProto>, 
Cloneable {
   public FetchImpl(Task.PullHost host, ShuffleType type, ExecutionBlockId 
executionBlockId,
                    int partitionId) {
     this(host, type, executionBlockId, partitionId, null, false, null,
-        new ArrayList<Integer>(), new ArrayList<Integer>());
+            new ArrayList<>(), new ArrayList<>());
   }
 
   public FetchImpl(Task.PullHost host, ShuffleType type, ExecutionBlockId 
executionBlockId,
                    int partitionId, List<Task.IntermediateEntry> 
intermediateEntryList) {
     this(host, type, executionBlockId, partitionId, null, false, null,
-        new ArrayList<Integer>(), new ArrayList<Integer>());
+            new ArrayList<>(), new ArrayList<>());
     for (Task.IntermediateEntry entry : intermediateEntryList){
       addPart(entry.getTaskId(), entry.getAttemptId());
     }

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core/src/main/java/org/apache/tajo/worker/TajoWorker.java
----------------------------------------------------------------------
diff --git a/tajo-core/src/main/java/org/apache/tajo/worker/TajoWorker.java 
b/tajo-core/src/main/java/org/apache/tajo/worker/TajoWorker.java
index bd23f19..4b0dac9 100644
--- a/tajo-core/src/main/java/org/apache/tajo/worker/TajoWorker.java
+++ b/tajo-core/src/main/java/org/apache/tajo/worker/TajoWorker.java
@@ -231,7 +231,7 @@ public class TajoWorker extends CompositeService {
 
     historyReader = new HistoryReader(workerContext.getWorkerName(), 
this.systemConf);
 
-    FunctionLoader.loadUserDefinedFunctions(systemConf, new 
HashMap<FunctionSignature, FunctionDesc>());
+    FunctionLoader.loadUserDefinedFunctions(systemConf, new HashMap<>());
 
     PythonScriptEngine.initPythonScriptEngineFiles();
     

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-core/src/main/java/org/apache/tajo/worker/TaskImpl.java
----------------------------------------------------------------------
diff --git a/tajo-core/src/main/java/org/apache/tajo/worker/TaskImpl.java 
b/tajo-core/src/main/java/org/apache/tajo/worker/TaskImpl.java
index a96e3bb..be920a1 100644
--- a/tajo-core/src/main/java/org/apache/tajo/worker/TaskImpl.java
+++ b/tajo-core/src/main/java/org/apache/tajo/worker/TaskImpl.java
@@ -148,7 +148,7 @@ public class TaskImpl implements Task {
       context.setOutputPath(outFilePath);
     }
 
-    this.localChunks = Collections.synchronizedList(new 
ArrayList<FileChunk>());
+    this.localChunks = Collections.synchronizedList(new ArrayList<>());
     LOG.info("==================================");
     LOG.info("* Stage " + request.getId() + " is initialized");
     LOG.info("* InterQuery: " + interQuery

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-jdbc/src/main/java/org/apache/tajo/jdbc/TajoDatabaseMetaData.java
----------------------------------------------------------------------
diff --git 
a/tajo-jdbc/src/main/java/org/apache/tajo/jdbc/TajoDatabaseMetaData.java 
b/tajo-jdbc/src/main/java/org/apache/tajo/jdbc/TajoDatabaseMetaData.java
index f9358a4..acb5b69 100644
--- a/tajo-jdbc/src/main/java/org/apache/tajo/jdbc/TajoDatabaseMetaData.java
+++ b/tajo-jdbc/src/main/java/org/apache/tajo/jdbc/TajoDatabaseMetaData.java
@@ -300,7 +300,7 @@ public class TajoDatabaseMetaData implements 
DatabaseMetaData {
         "PROCEDURE_TYPE"),
         Arrays.asList(Type.VARCHAR, Type.VARCHAR, Type.VARCHAR, Type.INT4, 
Type.INT4, Type.INT4,
             Type.VARCHAR, Type.INT2),
-        new ArrayList<MetaDataTuple>());
+            new ArrayList<MetaDataTuple>());
   }
 
   @Override
@@ -317,7 +317,7 @@ public class TajoDatabaseMetaData implements 
DatabaseMetaData {
             Type.INT2, Type.VARCHAR, Type.INT4, Type.INT4, Type.INT2,
             Type.INT2, Type.INT2, Type.VARCHAR, Type.VARCHAR, Type.INT2,
             Type.INT2, Type.INT2, Type.INT1, Type.VARCHAR, Type.VARCHAR),
-        new ArrayList<MetaDataTuple>());
+            new ArrayList<MetaDataTuple>());
   }
 
   /**
@@ -567,7 +567,7 @@ public class TajoDatabaseMetaData implements 
DatabaseMetaData {
         "IS_GRANTABLE"),
         Arrays.asList(Type.VARCHAR, Type.VARCHAR, Type.VARCHAR, Type.VARCHAR, 
Type.VARCHAR, Type.VARCHAR,
             Type.VARCHAR, Type.VARCHAR),
-        new ArrayList<MetaDataTuple>());
+            new ArrayList<MetaDataTuple>());
   }
 
   @Override
@@ -576,7 +576,7 @@ public class TajoDatabaseMetaData implements 
DatabaseMetaData {
     return new TajoMetaDataResultSet(Arrays.asList("TABLE_CAT", "TABLE_SCHEM",
         "TABLE_NAME", "GRANTOR", "GRANTEE", "PRIVILEGE", "IS_GRANTABLE"),
         Arrays.asList(Type.VARCHAR, Type.VARCHAR, Type.VARCHAR, Type.VARCHAR, 
Type.VARCHAR, Type.VARCHAR, Type.VARCHAR),
-        new ArrayList<MetaDataTuple>());
+            new ArrayList<MetaDataTuple>());
   }
 
   @Override
@@ -585,7 +585,7 @@ public class TajoDatabaseMetaData implements 
DatabaseMetaData {
     return new TajoMetaDataResultSet(Arrays.asList("SCOPE", "COLUMN_NAME",
         "DATA_TYPE", "TYPE_NAME", "COLUMN_SIZE", "BUFFER_LENGTH", 
"DECIMAL_DIGITS", "PSEUDO_COLUMN"),
         Arrays.asList(Type.INT2, Type.VARCHAR, Type.INT2, Type.VARCHAR, 
Type.INT4, Type.INT4, Type.INT2, Type.INT2),
-        new ArrayList<MetaDataTuple>());
+            new ArrayList<MetaDataTuple>());
   }
 
   @Override
@@ -594,7 +594,7 @@ public class TajoDatabaseMetaData implements 
DatabaseMetaData {
     return new TajoMetaDataResultSet(Arrays.asList("SCOPE", "COLUMN_NAME",
         "DATA_TYPE", "TYPE_NAME", "COLUMN_SIZE", "BUFFER_LENGTH", 
"DECIMAL_DIGITS", "PSEUDO_COLUMN"),
         Arrays.asList(Type.INT2, Type.VARCHAR, Type.INT2, Type.VARCHAR, 
Type.INT4, Type.INT4, Type.INT2, Type.INT2),
-        new ArrayList<MetaDataTuple>());
+            new ArrayList<MetaDataTuple>());
   }
 
   @Override
@@ -782,7 +782,7 @@ public class TajoDatabaseMetaData implements 
DatabaseMetaData {
       throws SQLException {
     return new TajoMetaDataResultSet(Arrays.asList("NAME", "MAX_LEN", 
"DEFAULT_VALUE", "DESCRIPTION"),
         Arrays.asList(Type.VARCHAR, Type.INT4, Type.VARCHAR, Type.VARCHAR),
-        new ArrayList<MetaDataTuple>());
+            new ArrayList<MetaDataTuple>());
   }
 
   @Override

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-plan/src/main/java/org/apache/tajo/plan/ExprAnnotator.java
----------------------------------------------------------------------
diff --git a/tajo-plan/src/main/java/org/apache/tajo/plan/ExprAnnotator.java 
b/tajo-plan/src/main/java/org/apache/tajo/plan/ExprAnnotator.java
index f4c11cd..560f6ac 100644
--- a/tajo-plan/src/main/java/org/apache/tajo/plan/ExprAnnotator.java
+++ b/tajo-plan/src/main/java/org/apache/tajo/plan/ExprAnnotator.java
@@ -97,7 +97,7 @@ public class ExprAnnotator extends 
BaseAlgebraVisitor<ExprAnnotator.Context, Eva
   public EvalNode createEvalNode(LogicalPlanner.PlanContext planContext, Expr 
expr,
                                  NameResolvingMode colRsvLevel, boolean 
includeSeflDescTable) throws TajoException {
     Context context = new Context(planContext, colRsvLevel, 
includeSeflDescTable);
-    return planContext.evalOptimizer.optimize(planContext, visit(context, new 
Stack<Expr>(), expr));
+    return planContext.evalOptimizer.optimize(planContext, visit(context, new 
Stack<>(), expr));
   }
 
   public static void assertEval(boolean condition, String message) throws 
TajoException {

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-plan/src/main/java/org/apache/tajo/plan/ExprNormalizer.java
----------------------------------------------------------------------
diff --git a/tajo-plan/src/main/java/org/apache/tajo/plan/ExprNormalizer.java 
b/tajo-plan/src/main/java/org/apache/tajo/plan/ExprNormalizer.java
index ab1914b..d66263f 100644
--- a/tajo-plan/src/main/java/org/apache/tajo/plan/ExprNormalizer.java
+++ b/tajo-plan/src/main/java/org/apache/tajo/plan/ExprNormalizer.java
@@ -120,7 +120,7 @@ class ExprNormalizer extends 
SimpleAlgebraVisitor<ExprNormalizer.ExprNormalizedR
     ExprNormalizedResult exprNormalizedResult = new 
ExprNormalizedResult(context, subexprElimination);
     Stack<Expr> stack = new Stack<>();
     stack.push(expr);
-    visit(exprNormalizedResult, new Stack<Expr>(), expr);
+    visit(exprNormalizedResult, new Stack<>(), expr);
     exprNormalizedResult.baseExpr = stack.pop();
     return exprNormalizedResult;
   }
@@ -180,13 +180,13 @@ class ExprNormalizer extends 
SimpleAlgebraVisitor<ExprNormalizer.ExprNormalizedR
   public Expr visitBinaryOperator(ExprNormalizedResult ctx, Stack<Expr> stack, 
BinaryOperator expr) throws TajoException {
     stack.push(expr);
 
-    visit(ctx, new Stack<Expr>(), expr.getLeft());
+    visit(ctx, new Stack<>(), expr.getLeft());
     if (isBinaryCommonTermsElimination(ctx, expr.getLeft())) {
       String refName = ctx.block.namedExprsMgr.addExpr(expr.getLeft());
       expr.setLeft(new ColumnReferenceExpr(refName));
     }
 
-    visit(ctx, new Stack<Expr>(), expr.getRight());
+    visit(ctx, new Stack<>(), expr.getRight());
     if (isBinaryCommonTermsElimination(ctx, expr.getRight())) {
       String refName = ctx.block.namedExprsMgr.addExpr(expr.getRight());
       expr.setRight(new ColumnReferenceExpr(refName));

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-plan/src/main/java/org/apache/tajo/plan/LogicalOptimizer.java
----------------------------------------------------------------------
diff --git a/tajo-plan/src/main/java/org/apache/tajo/plan/LogicalOptimizer.java 
b/tajo-plan/src/main/java/org/apache/tajo/plan/LogicalOptimizer.java
index e3b3843..cbc05da 100644
--- a/tajo-plan/src/main/java/org/apache/tajo/plan/LogicalOptimizer.java
+++ b/tajo-plan/src/main/java/org/apache/tajo/plan/LogicalOptimizer.java
@@ -119,7 +119,7 @@ public class LogicalOptimizer {
 
       JoinTargetCollector collector = new JoinTargetCollector();
       Set<Target> targets = new LinkedHashSet<>();
-      collector.visitJoin(targets, plan, block, old, new Stack<LogicalNode>());
+      collector.visitJoin(targets, plan, block, old, new Stack<>());
 
       if (targets.size() == 0) {
         
newJoinNode.setTargets(PlannerUtil.schemaToTargets(old.getOutSchema()));
@@ -460,7 +460,7 @@ public class LogicalOptimizer {
     RelationNodeFinderContext context = new RelationNodeFinderContext();
     context.findMostLeft = true;
     RelationNodeFinder finder = new RelationNodeFinder();
-    finder.visit(context, plan, block, from, new Stack<LogicalNode>());
+    finder.visit(context, plan, block, from, new Stack<>());
     return context.founds.isEmpty() ? null : context.founds.iterator().next();
   }
 
@@ -478,7 +478,7 @@ public class LogicalOptimizer {
     RelationNodeFinderContext context = new RelationNodeFinderContext();
     context.findMostRight = true;
     RelationNodeFinder finder = new RelationNodeFinder();
-    finder.visit(context, plan, block, from, new Stack<LogicalNode>());
+    finder.visit(context, plan, block, from, new Stack<>());
     return context.founds.isEmpty() ? null : context.founds.iterator().next();
   }
 

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-plan/src/main/java/org/apache/tajo/plan/LogicalPlan.java
----------------------------------------------------------------------
diff --git a/tajo-plan/src/main/java/org/apache/tajo/plan/LogicalPlan.java 
b/tajo-plan/src/main/java/org/apache/tajo/plan/LogicalPlan.java
index 457cb2c..04b846f 100644
--- a/tajo-plan/src/main/java/org/apache/tajo/plan/LogicalPlan.java
+++ b/tajo-plan/src/main/java/org/apache/tajo/plan/LogicalPlan.java
@@ -521,7 +521,7 @@ public class LogicalPlan {
       }
       canonicalNameToRelationMap.put(relation.getCanonicalName(), relation);
       relationList.add(relation);
-      relNodePidAccessPathMap.put(relation.getPID(), new 
ArrayList<AccessPathInfo>());
+      relNodePidAccessPathMap.put(relation.getPID(), new ArrayList<>());
     }
 
     public void addRelation(RelationNode relation, List<AccessPathInfo> 
accessPathInfos) {
@@ -530,7 +530,7 @@ public class LogicalPlan {
       }
       canonicalNameToRelationMap.put(relation.getCanonicalName(), relation);
       relationList.add(relation);
-      relNodePidAccessPathMap.put(relation.getPID(), new 
ArrayList<AccessPathInfo>());
+      relNodePidAccessPathMap.put(relation.getPID(), new ArrayList<>());
     }
 
     public void addAccessPath(RelationNode relation, AccessPathInfo 
accessPathInfo) {

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-plan/src/main/java/org/apache/tajo/plan/LogicalPlanner.java
----------------------------------------------------------------------
diff --git a/tajo-plan/src/main/java/org/apache/tajo/plan/LogicalPlanner.java 
b/tajo-plan/src/main/java/org/apache/tajo/plan/LogicalPlanner.java
index a140bd2..92f925a 100644
--- a/tajo-plan/src/main/java/org/apache/tajo/plan/LogicalPlanner.java
+++ b/tajo-plan/src/main/java/org/apache/tajo/plan/LogicalPlanner.java
@@ -163,7 +163,7 @@ public class LogicalPlanner extends 
BaseAlgebraVisitor<LogicalPlanner.PlanContex
     PlanContext context = new PlanContext(queryContext, plan, rootBlock, 
evalOptimizer, debug);
     preprocessor.process(context, expr);
     plan.resetGeneratedId();
-    LogicalNode topMostNode = this.visit(context, new Stack<Expr>(), expr);
+    LogicalNode topMostNode = this.visit(context, new Stack<>(), expr);
 
     // Add Root Node
     LogicalRootNode root = plan.createNode(LogicalRootNode.class);
@@ -1431,7 +1431,7 @@ public class LogicalPlanner extends 
BaseAlgebraVisitor<LogicalPlanner.PlanContex
 
     PlanContext newContext = new PlanContext(context, childBlock);
     context.plan.connectBlocks(childBlock, context.queryBlock, 
BlockType.TableSubQuery);
-    LogicalNode child = visit(newContext, new Stack<Expr>(), 
expr.getSubQuery());
+    LogicalNode child = visit(newContext, new Stack<>(), expr.getSubQuery());
     TableSubQueryNode subQueryNode = currentBlock.getNodeFromExpr(expr);
 
     subQueryNode.setSubQuery(child);
@@ -1574,7 +1574,7 @@ public class LogicalPlanner extends 
BaseAlgebraVisitor<LogicalPlanner.PlanContex
     QueryBlock leftBlock = context.plan.getBlockByExpr(setOperation.getLeft());
     PlanContext leftContext = new PlanContext(context, leftBlock);
     stack.push(setOperation);
-    LogicalNode leftChild = visit(leftContext, new Stack<Expr>(), 
setOperation.getLeft());
+    LogicalNode leftChild = visit(leftContext, new Stack<>(), 
setOperation.getLeft());
     stack.pop();
     // Connect left child and current blocks
     context.plan.connectBlocks(leftContext.queryBlock, context.queryBlock, 
BlockType.TableSubQuery);
@@ -1585,7 +1585,7 @@ public class LogicalPlanner extends 
BaseAlgebraVisitor<LogicalPlanner.PlanContex
     QueryBlock rightBlock = 
context.plan.getBlockByExpr(setOperation.getRight());
     PlanContext rightContext = new PlanContext(context, rightBlock);
     stack.push(setOperation);
-    LogicalNode rightChild = visit(rightContext, new Stack<Expr>(), 
setOperation.getRight());
+    LogicalNode rightChild = visit(rightContext, new Stack<>(), 
setOperation.getRight());
     stack.pop();
     // Connect right child and current blocks
     context.plan.connectBlocks(rightContext.queryBlock, context.queryBlock, 
BlockType.TableSubQuery);

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-plan/src/main/java/org/apache/tajo/plan/TypeDeterminant.java
----------------------------------------------------------------------
diff --git a/tajo-plan/src/main/java/org/apache/tajo/plan/TypeDeterminant.java 
b/tajo-plan/src/main/java/org/apache/tajo/plan/TypeDeterminant.java
index af413ca..1ff297f 100644
--- a/tajo-plan/src/main/java/org/apache/tajo/plan/TypeDeterminant.java
+++ b/tajo-plan/src/main/java/org/apache/tajo/plan/TypeDeterminant.java
@@ -51,7 +51,7 @@ public class TypeDeterminant extends 
SimpleAlgebraVisitor<LogicalPlanner.PlanCon
   }
 
   public DataType determineDataType(LogicalPlanner.PlanContext ctx, Expr expr) 
throws TajoException {
-    return visit(ctx, new Stack<Expr>(), expr);
+    return visit(ctx, new Stack<>(), expr);
   }
 
   @Override

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-plan/src/main/java/org/apache/tajo/plan/expr/AlgebraicUtil.java
----------------------------------------------------------------------
diff --git 
a/tajo-plan/src/main/java/org/apache/tajo/plan/expr/AlgebraicUtil.java 
b/tajo-plan/src/main/java/org/apache/tajo/plan/expr/AlgebraicUtil.java
index ef5cf08..55e439e 100644
--- a/tajo-plan/src/main/java/org/apache/tajo/plan/expr/AlgebraicUtil.java
+++ b/tajo-plan/src/main/java/org/apache/tajo/plan/expr/AlgebraicUtil.java
@@ -205,7 +205,7 @@ public class AlgebraicUtil {
    * @return the simplified expr
    */
   public static EvalNode eliminateConstantExprs(EvalNode expr) {
-    return algebraicOptimizer.visit(null, expr, new Stack<EvalNode>());
+    return algebraicOptimizer.visit(null, expr, new Stack<>());
   }
   
   /** 

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-plan/src/main/java/org/apache/tajo/plan/expr/EvalTreeUtil.java
----------------------------------------------------------------------
diff --git 
a/tajo-plan/src/main/java/org/apache/tajo/plan/expr/EvalTreeUtil.java 
b/tajo-plan/src/main/java/org/apache/tajo/plan/expr/EvalTreeUtil.java
index fe1c373..02ec615 100644
--- a/tajo-plan/src/main/java/org/apache/tajo/plan/expr/EvalTreeUtil.java
+++ b/tajo-plan/src/main/java/org/apache/tajo/plan/expr/EvalTreeUtil.java
@@ -46,7 +46,7 @@ public class EvalTreeUtil {
   public static int replace(EvalNode expr, EvalNode targetExpr, EvalNode 
tobeReplaced) {
     EvalReplaceVisitor replacer = new EvalReplaceVisitor(targetExpr, 
tobeReplaced);
     ReplaceContext context = new ReplaceContext();
-    replacer.visit(context, expr, new Stack<EvalNode>());
+    replacer.visit(context, expr, new Stack<>());
     return context.countOfReplaces;
   }
 
@@ -511,13 +511,13 @@ public class EvalTreeUtil {
 
   public static <T extends EvalNode> Collection<T> findEvalsByType(EvalNode 
evalNode, EvalType type) {
     EvalFinder finder = new EvalFinder(type);
-    finder.visit(null, evalNode, new Stack<EvalNode>());
+    finder.visit(null, evalNode, new Stack<>());
     return (Collection<T>) finder.evalNodes;
   }
 
   public static <T extends EvalNode> Collection<T> 
findOuterJoinSensitiveEvals(EvalNode evalNode) {
     OuterJoinSensitiveEvalFinder finder = new OuterJoinSensitiveEvalFinder();
-    finder.visit(null, evalNode, new Stack<EvalNode>());
+    finder.visit(null, evalNode, new Stack<>());
     return (Collection<T>) finder.evalNodes;
   }
 

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-plan/src/main/java/org/apache/tajo/plan/exprrewrite/rules/ConstantFolding.java
----------------------------------------------------------------------
diff --git 
a/tajo-plan/src/main/java/org/apache/tajo/plan/exprrewrite/rules/ConstantFolding.java
 
b/tajo-plan/src/main/java/org/apache/tajo/plan/exprrewrite/rules/ConstantFolding.java
index 63e921e..96186d3 100644
--- 
a/tajo-plan/src/main/java/org/apache/tajo/plan/exprrewrite/rules/ConstantFolding.java
+++ 
b/tajo-plan/src/main/java/org/apache/tajo/plan/exprrewrite/rules/ConstantFolding.java
@@ -38,7 +38,7 @@ public class ConstantFolding extends 
SimpleEvalNodeVisitor<LogicalPlanner.PlanCo
 
   @Override
   public EvalNode optimize(LogicalPlanner.PlanContext context, EvalNode 
evalNode) {
-    return visit(context, evalNode, new Stack<EvalNode>());
+    return visit(context, evalNode, new Stack<>());
   }
 
   @Override

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-plan/src/main/java/org/apache/tajo/plan/exprrewrite/rules/ConstantPropagation.java
----------------------------------------------------------------------
diff --git 
a/tajo-plan/src/main/java/org/apache/tajo/plan/exprrewrite/rules/ConstantPropagation.java
 
b/tajo-plan/src/main/java/org/apache/tajo/plan/exprrewrite/rules/ConstantPropagation.java
index 24488bd..c24578e 100644
--- 
a/tajo-plan/src/main/java/org/apache/tajo/plan/exprrewrite/rules/ConstantPropagation.java
+++ 
b/tajo-plan/src/main/java/org/apache/tajo/plan/exprrewrite/rules/ConstantPropagation.java
@@ -46,7 +46,7 @@ public class ConstantPropagation extends 
SimpleEvalNodeVisitor<LogicalPlanner.Pl
         return evalNode; // otherwise, it just returns.
       }
     } else {
-      return visit(context, evalNode, new Stack<EvalNode>());
+      return visit(context, evalNode, new Stack<>());
     }
   }
 

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/BaseSchemaBuildPhase.java
----------------------------------------------------------------------
diff --git 
a/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/BaseSchemaBuildPhase.java
 
b/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/BaseSchemaBuildPhase.java
index e41b7a7..b30cee4 100644
--- 
a/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/BaseSchemaBuildPhase.java
+++ 
b/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/BaseSchemaBuildPhase.java
@@ -68,7 +68,7 @@ public class BaseSchemaBuildPhase extends 
LogicalPlanPreprocessPhase {
 
   @Override
   public LogicalNode process(PlanContext context, Expr expr) throws 
TajoException {
-    return processor.visit(context, new Stack<Expr>(), expr);
+    return processor.visit(context, new Stack<>(), expr);
   }
   
   static class Processor extends BaseAlgebraVisitor<PlanContext, LogicalNode> {
@@ -345,13 +345,13 @@ public class BaseSchemaBuildPhase extends 
LogicalPlanPreprocessPhase {
         throws TajoException {
       LogicalPlan.QueryBlock leftBlock = ctx.getPlan().newQueryBlock();
       LogicalPlanner.PlanContext leftContext = new 
LogicalPlanner.PlanContext(ctx, leftBlock);
-      LogicalNode leftChild = visit(leftContext, new Stack<Expr>(), 
expr.getLeft());
+      LogicalNode leftChild = visit(leftContext, new Stack<>(), 
expr.getLeft());
       leftBlock.setRoot(leftChild);
       ctx.getQueryBlock().registerExprWithNode(expr.getLeft(), leftChild);
 
       LogicalPlan.QueryBlock rightBlock = ctx.getPlan().newQueryBlock();
       LogicalPlanner.PlanContext rightContext = new 
LogicalPlanner.PlanContext(ctx, rightBlock);
-      LogicalNode rightChild = visit(rightContext, new Stack<Expr>(), 
expr.getRight());
+      LogicalNode rightChild = visit(rightContext, new Stack<>(), 
expr.getRight());
       rightBlock.setRoot(rightChild);
       ctx.getQueryBlock().registerExprWithNode(expr.getRight(), rightChild);
 
@@ -571,7 +571,7 @@ public class BaseSchemaBuildPhase extends 
LogicalPlanPreprocessPhase {
 
       public static void normalize(LogicalPlanner.PlanContext context, Expr 
expr) throws TajoException {
         NameRefInSelectListNormalizer normalizer = new 
NameRefInSelectListNormalizer();
-        normalizer.visit(context,new Stack<Expr>(), expr);
+        normalizer.visit(context, new Stack<>(), expr);
       }
 
       @Override

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/rules/AccessPathRewriter.java
----------------------------------------------------------------------
diff --git 
a/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/rules/AccessPathRewriter.java
 
b/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/rules/AccessPathRewriter.java
index 8f3fbe7..7ba5f8b 100644
--- 
a/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/rules/AccessPathRewriter.java
+++ 
b/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/rules/AccessPathRewriter.java
@@ -72,7 +72,7 @@ public class AccessPathRewriter implements 
LogicalPlanRewriteRule {
     LogicalPlan plan = context.getPlan();
     LogicalPlan.QueryBlock rootBlock = plan.getRootBlock();
     rewriter.init(context.getQueryContext());
-    rewriter.visit(rootBlock, plan, rootBlock, rootBlock.getRoot(), new 
Stack<LogicalNode>());
+    rewriter.visit(rootBlock, plan, rootBlock, rootBlock.getRoot(), new 
Stack<>());
     return plan;
   }
 

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/rules/CommonConditionReduceRule.java
----------------------------------------------------------------------
diff --git 
a/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/rules/CommonConditionReduceRule.java
 
b/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/rules/CommonConditionReduceRule.java
index 5524256..c536e38 100644
--- 
a/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/rules/CommonConditionReduceRule.java
+++ 
b/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/rules/CommonConditionReduceRule.java
@@ -86,7 +86,7 @@ public class CommonConditionReduceRule implements 
LogicalPlanRewriteRule {
     @Override
     public LogicalNode visitFilter(Object context, LogicalPlan plan, 
LogicalPlan.QueryBlock block,
                                    SelectionNode selNode, Stack<LogicalNode> 
stack) throws TajoException {
-      selNode.setQual(evalRewriter.visit(null, selNode.getQual(), new 
Stack<EvalNode>()));
+      selNode.setQual(evalRewriter.visit(null, selNode.getQual(), new 
Stack<>()));
       return null;
     }
 
@@ -94,7 +94,7 @@ public class CommonConditionReduceRule implements 
LogicalPlanRewriteRule {
     public LogicalNode visitJoin(Object context, LogicalPlan plan, 
LogicalPlan.QueryBlock block,
                                  JoinNode joinNode, Stack<LogicalNode> stack) 
throws TajoException {
       if (joinNode.hasJoinQual()) {
-        joinNode.setJoinQual(evalRewriter.visit(null, joinNode.getJoinQual(), 
new Stack<EvalNode>()));
+        joinNode.setJoinQual(evalRewriter.visit(null, joinNode.getJoinQual(), 
new Stack<>()));
       }
       return null;
     }

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/rules/FilterPushDownRule.java
----------------------------------------------------------------------
diff --git 
a/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/rules/FilterPushDownRule.java
 
b/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/rules/FilterPushDownRule.java
index e44bba5..c4bcc33 100644
--- 
a/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/rules/FilterPushDownRule.java
+++ 
b/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/rules/FilterPushDownRule.java
@@ -115,7 +115,7 @@ public class FilterPushDownRule extends 
BasicLogicalPlanVisitor<FilterPushDownCo
     catalog = rewriteRuleContext.getCatalog();
     for (LogicalPlan.QueryBlock block : plan.getQueryBlocks()) {
       context.clear();
-      this.visit(context, plan, block, block.getRoot(), new 
Stack<LogicalNode>());
+      this.visit(context, plan, block, block.getRoot(), new Stack<>());
     }
 
     if (LOG.isDebugEnabled()) {

http://git-wip-us.apache.org/repos/asf/tajo/blob/5d470bc6/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/rules/InSubqueryRewriteRule.java
----------------------------------------------------------------------
diff --git 
a/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/rules/InSubqueryRewriteRule.java
 
b/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/rules/InSubqueryRewriteRule.java
index d0ff8b6..f221066 100644
--- 
a/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/rules/InSubqueryRewriteRule.java
+++ 
b/tajo-plan/src/main/java/org/apache/tajo/plan/rewrite/rules/InSubqueryRewriteRule.java
@@ -81,7 +81,7 @@ public class InSubqueryRewriteRule implements 
LogicalPlanRewriteRule {
   public LogicalPlan rewrite(LogicalPlanRewriteRuleContext context) throws 
TajoException {
     LogicalPlan.QueryBlock rootBlock = context.getPlan().getRootBlock();
     LogicalPlan plan = context.getPlan();
-    rewriter.visit(context.getQueryContext(), plan, rootBlock, 
rootBlock.getRoot(), new Stack<LogicalNode>());
+    rewriter.visit(context.getQueryContext(), plan, rootBlock, 
rootBlock.getRoot(), new Stack<>());
     return plan;
   }
 

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