diff --git a/plugins/org.eclipse.objectteams.otequinox/src/org/eclipse/objectteams/internal/osgi/weaving/ASMByteCodeAnalyzer.java b/plugins/org.eclipse.objectteams.otequinox/src/org/eclipse/objectteams/internal/osgi/weaving/ASMByteCodeAnalyzer.java
index d55bf4c..92786cb 100644
--- a/plugins/org.eclipse.objectteams.otequinox/src/org/eclipse/objectteams/internal/osgi/weaving/ASMByteCodeAnalyzer.java
+++ b/plugins/org.eclipse.objectteams.otequinox/src/org/eclipse/objectteams/internal/osgi/weaving/ASMByteCodeAnalyzer.java
@@ -1,7 +1,7 @@
 /**********************************************************************
  * This file is part of "Object Teams Development Tooling"-Software
  * 
- * Copyright 2008, 2014 Oliver Frank and others.
+ * Copyright 2008, 2019 Oliver Frank and others.
  * 
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
@@ -42,11 +42,13 @@
 
 	public static class ClassInformation {
 		private int modifiers;
+		private String name;
 		private String superClassName;
 		private String[] superInterfaceNames;
 
 		ClassInformation(ClassReader classReader) {
 			this.modifiers = classReader.getAccess();
+			this.name = classReader.getClassName();
 			this.superClassName = classReader.getSuperName();
 			this.superInterfaceNames = classReader.getInterfaces();
 		}
@@ -72,6 +74,12 @@
 				}
 			return superInterfaceNames;
 		}
+
+		public String getName() {
+			if (this.name != null)
+				return this.name.replace('/', '.');
+			return "<no name>";
+		}
 	}
 
 	private Map<String, ClassInformation> classInformationMap =
diff --git a/plugins/org.eclipse.objectteams.otequinox/src/org/eclipse/objectteams/internal/osgi/weaving/DelegatingTransformer.java b/plugins/org.eclipse.objectteams.otequinox/src/org/eclipse/objectteams/internal/osgi/weaving/DelegatingTransformer.java
index df7d543..b340308 100644
--- a/plugins/org.eclipse.objectteams.otequinox/src/org/eclipse/objectteams/internal/osgi/weaving/DelegatingTransformer.java
+++ b/plugins/org.eclipse.objectteams.otequinox/src/org/eclipse/objectteams/internal/osgi/weaving/DelegatingTransformer.java
@@ -27,6 +27,7 @@
 import java.util.EnumSet;
 
 import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.objectteams.internal.osgi.weaving.ASMByteCodeAnalyzer.ClassInformation;
 import org.eclipse.objectteams.internal.osgi.weaving.OTWeavingHook.WeavingReason;
 import org.eclipse.objectteams.internal.osgi.weaving.OTWeavingHook.WeavingScheme;
 import org.eclipse.objectteams.internal.osgi.weaving.Util.ProfileKind;
@@ -125,6 +126,12 @@
 				// error output during redefinition tends to swallow the stack, print it now:
 				System.err.println("Error redefining "+clazz.getName());
 				e.printStackTrace();
+				ClassInformation classInformation = new ASMByteCodeAnalyzer().getClassInformation(bytecode, clazz.getName());
+				if (!classInformation.getName().equals(clazz.getName())) {
+					System.err.println("Name mismatch "+clazz.getName()+" vs "+classInformation.getName());
+				} else if (!classInformation.getSuperClassName().equals(clazz.getSuperclass().getName())) {
+					System.err.println("Superclass mismatch "+clazz.getSuperclass().getName()+" vs "+classInformation.getSuperClassName());
+				}
 				throw e;
 			}
 		}
diff --git a/plugins/org.eclipse.objectteams.otredyn/src/org/eclipse/objectteams/otredyn/bytecode/AbstractBoundClass.java b/plugins/org.eclipse.objectteams.otredyn/src/org/eclipse/objectteams/otredyn/bytecode/AbstractBoundClass.java
index 05349fe..81f872c 100644
--- a/plugins/org.eclipse.objectteams.otredyn/src/org/eclipse/objectteams/otredyn/bytecode/AbstractBoundClass.java
+++ b/plugins/org.eclipse.objectteams.otredyn/src/org/eclipse/objectteams/otredyn/bytecode/AbstractBoundClass.java
@@ -906,7 +906,7 @@
 		if (this.hierarchyIsCallinAffected)
 			return true;
 		AbstractBoundClass zuper = getSuperclass();
-		if (!zuper.isJavaLangObject()) {
+		if (zuper != null && !zuper.isJavaLangObject()) {
 			if (zuper.hierarchyIsCallinAffected())
 				return this.hierarchyIsCallinAffected = true;
 		}