diff --git a/src/debugger.cc b/src/debugger.cc
index 1ba0c73..2156482 100644
--- a/src/debugger.cc
+++ b/src/debugger.cc
@@ -592,7 +592,7 @@
   }
   if (c->IsInterface()) {
     // http://code.google.com/p/android/issues/detail?id=20856
-    superclassId = NULL;
+    superclassId = 0;
   } else {
     superclassId = gRegistry->Add(c->GetSuperClass());
   }