[
https://issues.apache.org/jira/browse/HIVE-11878?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14876034#comment-14876034
]
Ratandeep Ratti commented on HIVE-11878:
----------------------------------------
Hi [~ashutoshc]
Here's the complete stacktrace (You can generate this by applying patch
HIVE-11878_qtest.patch )
{noformat}
Tests run: 2, Failures: 1, Errors: 0, Skipped: 0
at
org.apache.calcite.prepare.CalcitePrepareImpl.perform(CalcitePrepareImpl.java:882)
at org.apache.calcite.tools.Frameworks.withPrepare(Frameworks.java:149)
at org.apache.calcite.tools.Frameworks.withPlanner(Frameworks.java:106)
at
org.apache.hadoop.hive.ql.parse.CalcitePlanner.getOptimizedAST(CalcitePlanner.java:617)
at
org.apache.hadoop.hive.ql.parse.CalcitePlanner.genOPTree(CalcitePlanner.java:252)
at
org.apache.hadoop.hive.ql.parse.SemanticAnalyzer.analyzeInternal(SemanticAnalyzer.java:10137)
at
org.apache.hadoop.hive.ql.parse.CalcitePlanner.analyzeInternal(CalcitePlanner.java:212)
at
org.apache.hadoop.hive.ql.parse.BaseSemanticAnalyzer.analyze(BaseSemanticAnalyzer.java:240)
at org.apache.hadoop.hive.ql.Driver.compile(Driver.java:428)
at org.apache.hadoop.hive.ql.Driver.compile(Driver.java:310)
at org.apache.hadoop.hive.ql.Driver.compileInternal(Driver.java:1150)
at org.apache.hadoop.hive.ql.Driver.runInternal(Driver.java:1203)
at org.apache.hadoop.hive.ql.Driver.run(Driver.java:1079)
at org.apache.hadoop.hive.ql.Driver.run(Driver.java:1069)
at
org.apache.hadoop.hive.cli.CliDriver.processLocalCmd(CliDriver.java:213)
at org.apache.hadoop.hive.cli.CliDriver.processCmd(CliDriver.java:165)
at org.apache.hadoop.hive.cli.CliDriver.processLine(CliDriver.java:376)
at org.apache.hadoop.hive.cli.CliDriver.processLine(CliDriver.java:311)
at
org.apache.hadoop.hive.ql.QTestUtil.executeClientInternal(QTestUtil.java:1033)
at
org.apache.hadoop.hive.ql.QTestUtil.executeClient(QTestUtil.java:1007)
at
org.apache.hadoop.hive.cli.TestCliDriver.runTest(TestCliDriver.java:146)
at
org.apache.hadoop.hive.cli.TestCliDriver.testCliDriver_test_classloader(TestCliDriver.java:130)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at junit.framework.TestCase.runTest(TestCase.java:176)
at junit.framework.TestCase.runBare(TestCase.java:141)
at junit.framework.TestResult$1.protect(TestResult.java:122)
at junit.framework.TestResult.runProtected(TestResult.java:142)
at junit.framework.TestResult.run(TestResult.java:125)
at junit.framework.TestCase.run(TestCase.java:129)
at junit.framework.TestSuite.runTest(TestSuite.java:255)
at junit.framework.TestSuite.run(TestSuite.java:250)
at
org.junit.internal.runners.JUnit38ClassRunner.run(JUnit38ClassRunner.java:84)
at
org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:264)
at
org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:153)
at
org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:124)
at
org.apache.maven.surefire.booter.ForkedBooter.invokeProviderInSameClassLoader(ForkedBooter.java:200)
at
org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:153)
at
org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:103)
Caused by: java.lang.ClassNotFoundException: TestClClassA
at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 60 more
{noformat}
> ClassNotFoundException can possibly occur if multiple jars are registered
> one at a time in Hive
> ------------------------------------------------------------------------------------------------
>
> Key: HIVE-11878
> URL: https://issues.apache.org/jira/browse/HIVE-11878
> Project: Hive
> Issue Type: Bug
> Components: Hive
> Affects Versions: 1.2.1
> Reporter: Ratandeep Ratti
> Assignee: Ratandeep Ratti
> Labels: URLClassLoader
> Attachments: HIVE-11878.patch, HIVE-11878_qtest.patch
>
>
> When we register a jar on the Hive console. Hive creates a fresh URL
> classloader which includes the path of the current jar to be registered and
> all the jar paths of the parent classloader. The parent classlaoder is the
> current ThreadContextClassLoader. Once the URLClassloader is created Hive
> sets that as the current ThreadContextClassloader.
> So if we register multiple jars in Hive, there will be multiple
> URLClassLoaders created, each classloader including the jars from its parent
> and the one extra jar to be registered. The last URLClassLoader created will
> end up as the current ThreadContextClassLoader. (See details:
> org.apache.hadoop.hive.ql.exec.Utilities#addToClassPath)
> Now here's an example in which the above strategy can lead to a CNF exception.
> We register 2 jars *j1* and *j2* in Hive console. *j1* contains the UDF class
> *c1* and internally relies on class *c2* in jar *j2*. We register *j1* first,
> the URLClassLoader *u1* is created and also set as the
> ThreadContextClassLoader. We register *j2* next, the new URLClassLoader
> created will be *u2* with *u1* as parent and *u2* becomes the new
> ThreadContextClassLoader. Note *u2* includes paths to both jars *j1* and *j2*
> whereas *u1* only has paths to *j1* (For details see:
> org.apache.hadoop.hive.ql.exec.Utilities#addToClassPath).
> Now when we register class *c1* under a temporary function in Hive, we load
> the class using {code} class.forName("c1", true,
> Thread.currentThread().getContextClassLoader()) {code} . The
> currentThreadContext class-loader is *u2*, and it has the path to the class
> *c1*, but note that Class-loaders work by delegating to parent class-loader
> first. In this case class *c1* will be found and *defined* by class-loader
> *u1*.
> Now *c1* from jar *j1* has *u1* as its class-loader. If a method (say
> initialize) is called in *c1*, which references the class *c2*, *c2* will not
> be found since the class-loader used to search for *c2* will be *u1* (Since
> the caller's class-loader is used to load a class)
> I've added a qtest to explain the problem. Please see the attached patch
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