diff --git a/jode/jode/expr/CheckNullOperator.java b/jode/jode/expr/CheckNullOperator.java
new file mode 100644
index 0000000..be2f35b
--- /dev/null
+++ b/jode/jode/expr/CheckNullOperator.java
@@ -0,0 +1,65 @@
+/* 
+ * CheckNullOperator (c) 1998 Jochen Hoenicke
+ *
+ * You may distribute under the terms of the GNU General Public License.
+ *
+ * IN NO EVENT SHALL JOCHEN HOENICKE BE LIABLE TO ANY PARTY FOR DIRECT,
+ * INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF
+ * THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF JOCHEN HOENICKE 
+ * HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * JOCHEN HOENICKE SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS"
+ * BASIS, AND JOCHEN HOENICKE HAS NO OBLIGATION TO PROVIDE MAINTENANCE,
+ * SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * $Id$
+ */
+
+package jode.decompiler;
+import jode.Type;
+
+/**
+ * This is a pseudo operator, which represents the check against null
+ * that jikes and javac generates for inner classes:
+ *
+ * <pre>
+ *   outer.new Inner()
+ * </pre>
+ * is translated by javac to
+ * <pre>
+ *   new Outer$Inner(outer ((void) DUP.getClass()));
+ * </pre>
+ * and by jikes to
+ * <pre>
+ *   new Outer$Inner(outer (DUP == null ? throw null));
+ * </pre>
+ */
+
+public class CheckNullOperator extends SimpleOperator {
+
+    public CheckNullOperator(Type type) {
+        super(type, 0, 1);
+        operandTypes[0] = type;
+    }
+
+    public int getPriority() {
+        return 200;
+    }
+
+    public int getOperandPriority(int i) {
+        return 0;
+    }
+
+    public String toString(String[] operands) {
+	/* There is no way to produce exactly the same code.
+	 * This is a good approximation.
+	 * op.getClass will throw a null pointer exception if operands[0]
+	 * is null, otherwise return something not equal to null.
+	 * The bad thing is that this isn't atomar.
+	 */
+	return "/*CHECK NULL*/ " + 
+	    operands[0] + ".getClass() != null ? " + operands[0] + " : null";
+    }
+}
diff --git a/jode/jode/flow/CreateCheckNull.java b/jode/jode/flow/CreateCheckNull.java
new file mode 100644
index 0000000..7d04bd1
--- /dev/null
+++ b/jode/jode/flow/CreateCheckNull.java
@@ -0,0 +1,105 @@
+/* 
+ * CreateCheckNull (c) 1998 Jochen Hoenicke
+ *
+ * You may distribute under the terms of the GNU General Public License.
+ *
+ * IN NO EVENT SHALL JOCHEN HOENICKE BE LIABLE TO ANY PARTY FOR DIRECT,
+ * INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF
+ * THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF JOCHEN HOENICKE 
+ * HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * JOCHEN HOENICKE SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS"
+ * BASIS, AND JOCHEN HOENICKE HAS NO OBLIGATION TO PROVIDE MAINTENANCE,
+ * SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * $Id$
+ */
+
+package jode.flow;
+import jode.decompiler.*;
+import jode.Type;
+
+public class CreateCheckNull {
+
+    /* Situation:
+     * 
+     * javac: 
+     *  DUP
+     *  stack_0.getClass();
+     *
+     * jikes:
+     *  DUP
+     *  if (!stack_0 != null)
+     *    throw null;
+     */
+
+    public static boolean transformJavac(InstructionContainer ic,
+					 StructuredBlock last) {
+        if (!(last.outer instanceof SequentialBlock)
+	    || !(ic.getInstruction() instanceof ComplexExpression)
+	    || !(last.outer.getSubBlocks()[0] instanceof SpecialBlock))
+            return false;
+
+	SpecialBlock dup = (SpecialBlock) last.outer.getSubBlocks()[0];
+	if (dup.type != SpecialBlock.DUP
+	    || dup.count != 1 || dup.depth != 0)
+	    return false;
+	   
+	ComplexExpression ce = (ComplexExpression) ic.getInstruction();
+
+	if (!(ce.getOperator() instanceof PopOperator)
+	    || !(ce.getSubExpressions()[0] instanceof InvokeOperator))
+	    return false;
+
+        InvokeOperator getClassCall
+	    = (InvokeOperator) ce.getSubExpressions()[0];
+	if (!getClassCall.getMethodName().equals("getClass")
+	    || !(getClassCall.getMethodType().toString()
+		 .equals("()Ljava/lang/Class;")))
+	    return false;
+
+	ic.setInstruction(new CheckNullOperator(Type.tUObject));
+	last.replace(last.outer);
+        return true;
+    }
+
+    public static boolean transformJikes(IfThenElseBlock ifBlock,
+					 StructuredBlock last) {
+        if (!(last.outer instanceof SequentialBlock)
+	    || !(last.outer.getSubBlocks()[0] instanceof SpecialBlock)
+	    || ifBlock.elseBlock != null
+	    || !(ifBlock.thenBlock instanceof ThrowBlock))
+            return false;
+	System.err.println("last.outer: "+last.outer);
+
+	SpecialBlock dup = (SpecialBlock) last.outer.getSubBlocks()[0];
+	if (dup.type != SpecialBlock.DUP
+	    || dup.count != 1 || dup.depth != 0)
+	    return false;
+	   
+	System.err.println("tick1");
+	/* negate the instruction back to its original state */
+	Expression expr = ifBlock.cond.negate();
+	System.err.println(expr);
+	if (!(expr instanceof CompareUnaryOperator)
+	    || expr.getOperator().getOperatorIndex() != Operator.NOTEQUALS_OP
+	    || !(expr.getOperator().getOperandType(0).isOfType(Type.tUObject)))
+	    return false;
+
+	System.err.println("tick2");
+	InstructionContainer ic = 
+	    new InstructionBlock(new CheckNullOperator(Type.tUObject));
+	ifBlock.flowBlock.removeSuccessor(ifBlock.thenBlock.jump);
+	ic.moveJump(ifBlock.jump);
+	if (last == ifBlock) {
+	    ic.replace(last.outer);
+	    last = ic;
+	} else {
+	    ic.replace(ifBlock);
+	    last.replace(last.outer);
+	}
+        return true;
+    }
+}
diff --git a/jode/test/ClassOpTest.java b/jode/test/ClassOpTest.java
new file mode 100644
index 0000000..cb85f2e
--- /dev/null
+++ b/jode/test/ClassOpTest.java
@@ -0,0 +1,14 @@
+package jode.test;
+
+public class ClassOpTest {
+    static void test1() {
+	Class c1 = ClassOpTest.class;
+	Class c2 = Object.class;
+	Class c3 = ClassOpTest.class;
+    }
+
+    void test2() {
+	Class c2 = Object.class;
+	Class c3 = ClassOpTest.class;
+    }
+}