Index: src/tools/org/h2/dev/fs/FilePathZip2.java
===================================================================
--- src/tools/org/h2/dev/fs/FilePathZip2.java	(revision 4586)
+++ src/tools/org/h2/dev/fs/FilePathZip2.java	(working copy)
@@ -398,7 +398,8 @@
 
     public synchronized FileLock tryLock(long position, long size, boolean shared) throws IOException {
         if (shared) {
-            return new FileLock(null, position, size, shared) {
+        	// Cast null to FileChannel to avoid JDK 1.7 ambiguity
+            return new FileLock((FileChannel) null, position, size, shared) {
 
                 @Override
                 public boolean isValid() {
Index: src/main/org/h2/store/fs/FilePathZip.java
===================================================================
--- src/main/org/h2/store/fs/FilePathZip.java	(revision 4586)
+++ src/main/org/h2/store/fs/FilePathZip.java	(working copy)
@@ -317,7 +317,8 @@
 
     public synchronized FileLock tryLock(long position, long size, boolean shared) throws IOException {
         if (shared) {
-            return new FileLock(null, position, size, shared) {
+        	// Cast null to FileChannel to avoid JDK 1.7 ambiguity
+            return new FileLock((FileChannel) null, position, size, shared) {
 
                 @Override
                 public boolean isValid() {
Index: src/main/org/h2/store/fs/FilePathMem.java
===================================================================
--- src/main/org/h2/store/fs/FilePathMem.java	(revision 4586)
+++ src/main/org/h2/store/fs/FilePathMem.java	(working copy)
@@ -295,7 +295,8 @@
                 return null;
             }
         }
-        FileLock lock = new FileLock(null, position, size, shared) {
+        // Cast null to FileChannel to avoid JDK 1.7 ambiguity
+        FileLock lock = new FileLock((FileChannel) null, position, size, shared) {
 
             @Override
             public boolean isValid() {