In the Java directory layer, DirectoryLayer.exists returns true unconditionally when not passed a path. This is different than the other bindings, which run through the normal exists check, but which I believe will still ultimately return true. The major difference is that in Java, no read version is obtained, which can cause behavior differences in the binding tester. This adds a call to get the read version to the Java testers when processing the DIRECTORY_EXISTS instruction.

bindings/java/src/test/com/apple/foundationdb/test/AsyncDirectoryExtension.java

@@ -170,7 +170,10 @@ class AsyncDirectoryExtension {
 			.thenAccept(children -> inst.push(Tuple.fromItems(children).pack()));
 		}
 		else if(op == DirectoryOperation.DIRECTORY_EXISTS) {
-			return inst.popParam()
+			// In Java, DirectoryLayer.exists can return true without doing any reads.
+			// Other bindings will always do a read, so we get a read version now to be compatible with that behavior.
+			return inst.readTcx.readAsync(tr -> tr.getReadVersion())
+			.thenComposeAsync(v -> inst.popParam())
 			.thenComposeAsync(count -> DirectoryUtil.popPaths(inst, StackUtils.getInt(count)))
 			.thenComposeAsync(path -> {
 				if(path.size() == 0)

bindings/java/src/test/com/apple/foundationdb/test/DirectoryExtension.java

@@ -160,6 +160,11 @@ class DirectoryExtension {
 				int count = StackUtils.getInt(inst.popParam().get());
 				List<List<String>> path = DirectoryUtil.popPaths(inst, count).get();
 				boolean exists;
+
+				// In Java, DirectoryLayer.exists can return true without doing any reads.
+				// Other bindings will always do a read, so we get a read version now to be compatible with that behavior.
+				inst.readTcx.read(tr -> tr.getReadVersion().join());
+
 				if(path.size() == 0)
 					exists = directory().exists(inst.readTcx).get();
 				else