--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/gov/nasa/jpf/jvm/bytecode/ARRAYLENGTH.java	Fri Jan 23 10:14:01 2015 -0800
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2014, United States Government, as represented by the
+ * Administrator of the National Aeronautics and Space Administration.
+ * All rights reserved.
+ *
+ * The Java Pathfinder core (jpf-core) platform is licensed under the
+ * Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ * 
+ *        http://www.apache.org/licenses/LICENSE-2.0. 
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and 
+ * limitations under the License.
+ */
+package gov.nasa.jpf.jvm.bytecode;
+
+import gov.nasa.jpf.vm.ElementInfo;
+import gov.nasa.jpf.vm.Instruction;
+import gov.nasa.jpf.vm.MJIEnv;
+import gov.nasa.jpf.vm.StackFrame;
+import gov.nasa.jpf.vm.ThreadInfo;
+
+
+/**
+ * Get length of array 
+ * ..., arrayref => ..., length
+ */
+public class ARRAYLENGTH extends Instruction implements JVMInstruction {
+    
+  protected int arrayRef;
+
+  /**
+   * only makes sense from an executeInstruction() or instructionExecuted() listener,
+   * it is undefined outside of insn exec notifications
+   */
+  public int getArrayRef (ThreadInfo ti){
+    if (ti.isPreExec()){
+      return peekArrayRef(ti);
+    } else {
+      return arrayRef;
+    }
+  }
+
+  public ElementInfo peekArrayElementInfo (ThreadInfo ti){
+    int aref = getArrayRef(ti);
+    return ti.getElementInfo(aref);
+  }
+  
+  @Override
+  public Instruction execute (ThreadInfo ti) {
+    StackFrame frame = ti.getModifiableTopFrame();
+
+    arrayRef = frame.pop();
+
+    if (arrayRef == MJIEnv.NULL){
+      return ti.createAndThrowException("java.lang.NullPointerException",
+                                        "array length of null object");
+    }
+
+    ElementInfo ei = ti.getElementInfo(arrayRef);
+    frame.push(ei.arrayLength(), false);
+
+    return getNext(ti);
+  }
+  
+  @Override
+  public int getByteCode () {
+    return 0xBE;
+  }
+  
+  @Override
+  public void accept(JVMInstructionVisitor insVisitor) {
+	  insVisitor.visit(this);
+  }
+
+  protected int peekArrayRef (ThreadInfo ti) {
+    return ti.getTopFrame().peek();
+  }
+}