1 files changed, 15 insertions, 1 deletions
diff --git a/exec/java-exec/src/main/java/org/apache/drill/exec/compile/MergeAdapter.java b/exec/java-exec/src/main/java/org/apache/drill/exec/compile/MergeAdapter.java
index 05e8ac171..3a01dda8d 100644
--- a/exec/java-exec/src/main/java/org/apache/drill/exec/compile/MergeAdapter.java
+++ b/exec/java-exec/src/main/java/org/apache/drill/exec/compile/MergeAdapter.java
@@ -141,7 +141,21 @@ class MergeAdapter extends ClassVisitor {
   public void visitEnd() {
     // add all the fields of the class we're going to merge.
     for (Iterator<?> it = classToMerge.fields.iterator(); it.hasNext();) {
-      ((FieldNode) it.next()).accept(this);
+
+      // Special handling for nested classes. Drill uses non-static nested
+      // "inner" classes in some templates. Prior versions of Drill would
+      // create the generated nested classes as static, then this line
+      // would copy the "this$0" field to convert the static nested class
+      // into a non-static inner class. However, that approach is not
+      // compatible with plain-old Java compilation. Now, Drill generates
+      // the nested classes as non-static inner classes. As a result, we
+      // do not want to copy the hidden fields; we'll end up with two if
+      // we do.
+
+      FieldNode field = (FieldNode) it.next();
+      if (! field.name.startsWith("this$")) {
+        field.accept(this);
+      }
     }
 
     // add all the methods that we to include.