jdk/test/com/sun/jdi/ReferrersTest.java - platform/libcore - Git at Google

 /*
  * Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */

 /**
  * @test
  * @bug 5089849
  * @summary Add support for backtracking reference graph.
  * @author jjh
  *
  * @run build TestScaffold VMConnection TargetListener TargetAdapter
  * @run compile -g ReferrersTest.java
  * @run driver ReferrersTest
  */

 /*
  *  To run this test do this:
  *     runregress -no ReferrersTest <cmd line options>
  *
  *  where <cmd line options> are the options to be used to
  *  launch the debuggee, with the classname prefixed with @@.
  *  For example, this would run java2d demo as the debuggee:
  *     runregress -no ReferrersTest -classpath
  *                                    $jdkDir/demo/jfc/Java2D/Java2Demo.jar \
  *                                    -client @@java2d.Java2Demo
  *
  * In this mode, the specified debuggee is launched in debug mode,
  * and the debugger waits for a keystroke before connecting to the debuggee.
  *
  * If <cmd line options> is not specified, then the ReferrersTarg class below
  * is run as the debuggee.
  */
 import com.sun.jdi.*;
 import com.sun.jdi.event.*;
 import com.sun.jdi.request.*;

 import java.util.*;

 class ReferrersFiller {
     // This many instances of this are created.
     static int FILLER_COUNT = 20000;
     static ReferrersFiller[] lotsAndLots = new ReferrersFiller[
                                                ReferrersFiller.FILLER_COUNT];
     int xx;
     ReferrersFiller(int p1) {
         xx = p1;
     }
 }

 class ReferrersTarg {
     // This many instances + 1 of this class are created.
     static int TARG_COUNT = 10;
     static ReferrersTarg theReferrersTarg;
     static ReferrersTarg[] allReferrersTargs;

     // Each instance will point to the theReferrersTarg
     ReferrersTarg oneReferrersTarg;

     public static void bkpt() {
     }

     public static void main(String[] args) {
         System.out.println("Howdy!");
         for (int ii = 0; ii < ReferrersFiller.lotsAndLots.length; ii++) {
             ReferrersFiller.lotsAndLots[ii] = new ReferrersFiller(ii);
         }

         theReferrersTarg = new ReferrersTarg();
         allReferrersTargs = new ReferrersTarg[ReferrersTarg.TARG_COUNT];
         for (int ii = 0; ii < ReferrersTarg.TARG_COUNT; ii++) {
             allReferrersTargs[ii] = new ReferrersTarg();
             allReferrersTargs[ii].oneReferrersTarg = theReferrersTarg;
         }
         bkpt();

         System.out.println("Goodbye from ReferrersTarg!");
     }
 }

 /********** test program **********/

 public class ReferrersTest extends TestScaffold {
     static String targetName = "ReferrersTarg";
     ReferenceType targetClass;
     ThreadReference mainThread;

     ReferrersTest(String args[]) {
         super(args);
     }

     public static void main(String[] args) throws Exception {
         /*
          * If args contains @@xxxx, then that is the
          * name of the class we are to run.
          */
         for (int ii = 0; ii < args.length; ii ++) {
             if (args[ii].startsWith("@@")) {
                 targetName = args[ii] = args[ii].substring(2);
                 break;
             }
         }
         new ReferrersTest(args).startTests();
     }

     /*
      * Used to sort a list of ReferenceTypes by
      * instance count.
      */
     class ToSort implements Comparable<ToSort> {
         long count;
         ReferenceType rt;

         public ToSort(long count, ReferenceType rt) {
             this.count = count;
             this.rt = rt;
         }

         public int compareTo(ToSort obj) {
             if (count < obj.count) return -1;
             if (count == obj.count) return 0;
             return 1;
         }
     }

     protected void runTests() throws Exception {
         /*
          * Get to the top of main()
          * to determine targetClass and mainThread
          */
         int CUT_OFF = 1000;
         BreakpointEvent bpe;
         bpe = startToMain(targetName);
         targetClass = bpe.location().declaringType();
         mainThread = bpe.thread();

         if (targetName.equals("ReferrersTarg")) {
             resumeTo("ReferrersTarg", "bkpt", "()V");
         } else {
             // Let debuggee run for awhile to get classes loaded
             vm().resume();
             try {
                 System.err.println("Press <enter> to continue");
                 System.in.read();
                 System.err.println("running...");

             } catch(Exception e) {
             }
             vm().suspend();
         }

         // Get all classes.
         long start = System.currentTimeMillis();
         List<ReferenceType> allClasses = vm().allClasses();
         long end = System.currentTimeMillis();
         System.out.println( allClasses.size() +
                             " classes from vm.allClasses() took " +
                             (end - start) + " ms");

         long[] counts;

         // Test for NPE
         {
             boolean pass = false;
             try {
                 counts = vm().instanceCounts(null);
             } catch (NullPointerException ee) {
                 pass = true;
             }
             if (!pass) {
                 failure("failure: NullPointerException not thrown on instanceCounts(null)");
             }
         }

         // Test for 0 length array
         {
             List<ReferenceType>someClasses = new ArrayList(2);
             counts = vm().instanceCounts(someClasses);
             if (counts.length != 0) {
                 failure("failure: instanceCounts with a zero length array fails: " +
                         counts.length);
             }
         }

         // Test various values of maxInstances
         if (targetClass.name().equals("ReferrersTarg")) {
             List<ObjectReference> noInstances = targetClass.instances(0);
             if (noInstances.size() != ReferrersTarg.TARG_COUNT + 1) {
                 failure("failure: instances(0): " + noInstances.size() + ", for " + targetClass);
             }
             noInstances = targetClass.instances(1);
             if (noInstances.size() != 1) {
                 failure("failure: instances(1): " + noInstances.size() + ", for " + targetClass);
             }
             boolean pass = false;
             try {
                 noInstances = targetClass.instances(-1);
             } catch (IllegalArgumentException ee) {
                 pass = true;
             }
             if (!pass) {
                 failure("failure: instances(-1) did not get an exception");
             }
         }

         // Instance counts for all classes
         start = System.currentTimeMillis();
         counts = vm().instanceCounts(allClasses);
         end = System.currentTimeMillis();

         if (counts.length == 0) {
             System.out.println("failure: No instances found");
             throw new Exception("ReferrersTest: failed");
         }

         // Create a list of ReferenceTypes sorted by instance count
         int size = 0;
         List<ToSort> sorted = new ArrayList(allClasses.size());
         for (int ii = 0; ii < allClasses.size(); ii++) {
             size += counts[ii];
             ToSort tos = new ToSort(counts[ii], allClasses.get(ii));
             sorted.add(tos);
         }

         System.out.println("instance counts for " + counts.length +
                            " classes got " + size + " instances and took " +
                             (end - start) + " ms");


         boolean gotReferrersFiller = false;
         boolean gotReferrersTarg = false;

         Collections.sort(sorted);
         for (int ii = sorted.size() - 1; ii >= 0 ; ii--) {
             ToSort xxx = sorted.get(ii);

             if (xxx.rt.name().equals("ReferrersFiller") &&
                 xxx.count == ReferrersFiller.FILLER_COUNT) {
                 gotReferrersFiller = true;
             }
             if (xxx.rt.name().equals("ReferrersTarg") &&
                 xxx.count == ReferrersTarg.TARG_COUNT + 1) {
                 gotReferrersTarg = true;
             }
         }
         if (!gotReferrersFiller) {
             failure("failure: Expected " + ReferrersFiller.FILLER_COUNT +
                         " instances of ReferrersFiller");
         }
         if (!gotReferrersTarg) {
             failure("failure: Expected " + (ReferrersTarg.TARG_COUNT + 1) +
                     " instances of ReferrersTarg");
         }

         List<List<ObjectReference>> allInstances = new ArrayList(10);

         // Instances, one class at a time, in sorted order, printing each line
         if (true) {
             System.out.println("\nGetting instances for one class " +
                                "at a time (limited) in sorted order");
             List<ReferenceType> rtList = new ArrayList(1);
             rtList.add(null);
             long start1 = System.currentTimeMillis();
             size = 0;
             long count = 0;
             for (int ii = sorted.size() - 1; ii >= 0 ; ii--) {
                 ToSort xxx = sorted.get(ii);
                 if (xxx.count <= CUT_OFF) {
                     break;
                 }
                 rtList.set(0, xxx.rt);
                 start = System.currentTimeMillis();
                 List<ObjectReference> oneInstances = xxx.rt.instances(19999999);
                 end = System.currentTimeMillis();
                 size += oneInstances.size();
                 count++;
                 System.out.println("Expected " + xxx.count + " instances, got " +
                                    oneInstances.size() +
                                    " instances for " + sorted.get(ii).rt +
                                    " in " + (end - start) + " ms");

                 if (xxx.rt.name().equals("ReferrersFiller") &&
                     oneInstances.size() != ReferrersFiller.FILLER_COUNT) {
                     failure("failure: Expected " + ReferrersFiller.FILLER_COUNT +
                             " instances of ReferrersFiller");
                 }
                 if (xxx.rt.name().equals("ReferrersTarg") &&
                     oneInstances.size() != ReferrersTarg.TARG_COUNT + 1) {
                     failure("failure: Expected " + (ReferrersTarg.TARG_COUNT + 1) +
                             " instances of ReferrersTarg");
                 }
                 allInstances.add(oneInstances);
             }

             end = System.currentTimeMillis();

             System.out.println(size + " instances via making one vm.instances" +
                                " call for each of " + count +
                                " classes took " + (end - start1) + " ms");
             System.out.println("Per class = " +
                                (end - start) / allClasses.size() + " ms");
         }


         // referrers

         // Test various values of maxReferrers
         if (targetClass.name().equals("ReferrersTarg")) {
             Field field1 = targetClass.fieldByName("theReferrersTarg");
             ObjectReference anInstance = (ObjectReference)targetClass.getValue(field1);
             List<ObjectReference> noReferrers = anInstance.referringObjects(0);
             if (noReferrers.size() != ReferrersTarg.TARG_COUNT + 1 ) {
                 failure("failure: referringObjects(0) got " + noReferrers.size() +
                         ", for " + anInstance);
             }
             noReferrers = anInstance.referringObjects(1);
             if (noReferrers.size() != 1 ) {
                 failure("failure: referringObjects(1) got " + noReferrers.size() +
                         ", for " + anInstance);
             }
             boolean pass = false;
             try {
                 noReferrers = anInstance.referringObjects(-1);
             } catch (IllegalArgumentException ee) {
                 pass = true;
             }
             if (!pass) {
                 failure("failure: referringObjects(-1) did not get an exception");
             }
         }

         List<ObjectReference> allReferrers = null;
         List<ObjectReference> someInstances = new ArrayList();
         if (targetName.equals("ReferrersTarg")) {
             Field field1 = targetClass.fieldByName("theReferrersTarg");
             ObjectReference val = (ObjectReference)targetClass.getValue(field1);
             someInstances.add(val);
             allReferrers = val.referringObjects(99999);  //LIMIT
             if (allReferrers.size() != ReferrersTarg.TARG_COUNT + 1) {
                 failure("failure: expected " + (ReferrersTarg.TARG_COUNT + 1) +
                         "referrers, but got " + allReferrers.size() +
                         " referrers for " + val);
             }
         } else {
             // referrers
             // Create someInstances to find the referrers of.
             for (int ii = 0; ii < allClasses.size(); ii++) {
                 List<ObjectReference> objRefList = allInstances.get(ii);
                 if (objRefList != null) {
                     int asize = objRefList.size();
                     if (false) {
                         System.out.println(asize + ", " + allClasses.get(ii));
                     }
                     // Remember one instance per class to get referrers
                     if (asize > 0) {
                         someInstances.add(objRefList.get(0));
                     }
                 }
             }
         }

         for (ObjectReference objRef: someInstances) {
             //System.out.println( "Getting referrers for " + objRef);
             start = System.currentTimeMillis();
             if ( true) {
                 showReferrers(objRef, 0, 0, 0);
             } else {
                 allReferrers = objRef.referringObjects(99999);  //LIMIT
                 end = System.currentTimeMillis();
                 if (true || allReferrers.size() > 1) {
                     System.out.println( allReferrers.size() + " referrers for " + objRef + " took " + (end - start) + " ms");
                 }
             }
         }

         /*
          * deal with results of test
          * if anything has called failure("foo") testFailed will be true
          */
         if (!testFailed) {
             println("ReferrersTest: passed");
         } else {
             throw new Exception("ReferrersTest: failed");
         }
     }
     void indent(int level) {
         for (int ii = 0; ii < level; ii++) {
             System.out.print("    ");
         }
     }


     Map<ObjectReference, Object> visited = new HashMap(100);
     void showReferrers(ObjectReference objRef, int level, int total, int which) {

         if (level == 0) {
             visited.clear();
         } else {
             if (visited.containsKey(objRef)) {
                 indent(level);
                 System.out.println("(" + which + ")" + ":<pruned> " + objRef);
                 return;
             }
             visited.put(objRef, null);
             indent(level);
             //System.out.println(which + "/" + total + ": " + objRef + " took " + time + " ms");
         }

         List<ObjectReference> allReferrers = null;

         //System.out.println( "Getting referrers for " + objRef);
         long start, end;
         start = System.currentTimeMillis();
         allReferrers = objRef.referringObjects(99999);  //LIMIT
         end = System.currentTimeMillis();

         if (which == 0) {
             System.out.println(allReferrers.size() + " referrers for " + objRef + " took " + (end - start) + " ms");
         } else {
             System.out.println("(" + which + ") "  + objRef);
             indent(level);
             System.out.println("    " + allReferrers.size() + " referrers for " + objRef + " took " + (end - start) + " ms");
         }

         // We have to stop going up a referrer chain in some cases
         Type rt = objRef.type();
         if (rt instanceof ClassType) {
             ClassType ct = (ClassType)rt;
             String name = ct.name();
             if (name.equals("sun.awt.SoftCache$ValueCell")) {
                 return;
             }
             if (name.equals("java.lang.ref.Finalizer")) {
                 return;
             }
             if (name.equals("java.lang.ref.SoftReference")) {
                 return;
             }
             // oh oh, should really check for a subclass of ClassLoader :-)
             if (name.indexOf("ClassLoader") >= 0) {
                 return;
             }
             // No doubt there are other reasons to stop ...
         }
         int itemNumber = 1;
         int allSize = allReferrers.size();
         for (ObjectReference objx: allReferrers) {
             showReferrers(objx, level + 1, allSize, itemNumber++);
         }
     }
 }
	/*
	* Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	/**
	* @test
	* @bug 5089849
	* @summary Add support for backtracking reference graph.
	* @author jjh
	*
	* @run build TestScaffold VMConnection TargetListener TargetAdapter
	* @run compile -g ReferrersTest.java
	* @run driver ReferrersTest
	*/

	/*
	* To run this test do this:
	* runregress -no ReferrersTest <cmd line options>
	*
	* where <cmd line options> are the options to be used to
	* launch the debuggee, with the classname prefixed with @@.
	* For example, this would run java2d demo as the debuggee:
	* runregress -no ReferrersTest -classpath
	* $jdkDir/demo/jfc/Java2D/Java2Demo.jar \
	* -client @@java2d.Java2Demo
	*
	* In this mode, the specified debuggee is launched in debug mode,
	* and the debugger waits for a keystroke before connecting to the debuggee.
	*
	* If <cmd line options> is not specified, then the ReferrersTarg class below
	* is run as the debuggee.
	*/
	import com.sun.jdi.*;
	import com.sun.jdi.event.*;
	import com.sun.jdi.request.*;

	import java.util.*;

	class ReferrersFiller {
	// This many instances of this are created.
	static int FILLER_COUNT = 20000;
	static ReferrersFiller[] lotsAndLots = new ReferrersFiller[
	ReferrersFiller.FILLER_COUNT];
	int xx;
	ReferrersFiller(int p1) {
	xx = p1;
	}
	}

	class ReferrersTarg {
	// This many instances + 1 of this class are created.
	static int TARG_COUNT = 10;
	static ReferrersTarg theReferrersTarg;
	static ReferrersTarg[] allReferrersTargs;

	// Each instance will point to the theReferrersTarg
	ReferrersTarg oneReferrersTarg;

	public static void bkpt() {
	}

	public static void main(String[] args) {
	System.out.println("Howdy!");
	for (int ii = 0; ii < ReferrersFiller.lotsAndLots.length; ii++) {
	ReferrersFiller.lotsAndLots[ii] = new ReferrersFiller(ii);
	}

	theReferrersTarg = new ReferrersTarg();
	allReferrersTargs = new ReferrersTarg[ReferrersTarg.TARG_COUNT];
	for (int ii = 0; ii < ReferrersTarg.TARG_COUNT; ii++) {
	allReferrersTargs[ii] = new ReferrersTarg();
	allReferrersTargs[ii].oneReferrersTarg = theReferrersTarg;
	}
	bkpt();

	System.out.println("Goodbye from ReferrersTarg!");
	}
	}

	/******** test program ********/

	public class ReferrersTest extends TestScaffold {
	static String targetName = "ReferrersTarg";
	ReferenceType targetClass;
	ThreadReference mainThread;

	ReferrersTest(String args[]) {
	super(args);
	}

	public static void main(String[] args) throws Exception {
	/*
	* If args contains @@xxxx, then that is the
	* name of the class we are to run.
	*/
	for (int ii = 0; ii < args.length; ii ++) {
	if (args[ii].startsWith("@@")) {
	targetName = args[ii] = args[ii].substring(2);
	break;
	}
	}
	new ReferrersTest(args).startTests();
	}

	/*
	* Used to sort a list of ReferenceTypes by
	* instance count.
	*/
	class ToSort implements Comparable<ToSort> {
	long count;
	ReferenceType rt;

	public ToSort(long count, ReferenceType rt) {
	this.count = count;
	this.rt = rt;
	}

	public int compareTo(ToSort obj) {
	if (count < obj.count) return -1;
	if (count == obj.count) return 0;
	return 1;
	}
	}

	protected void runTests() throws Exception {
	/*
	* Get to the top of main()
	* to determine targetClass and mainThread
	*/
	int CUT_OFF = 1000;
	BreakpointEvent bpe;
	bpe = startToMain(targetName);
	targetClass = bpe.location().declaringType();
	mainThread = bpe.thread();

	if (targetName.equals("ReferrersTarg")) {
	resumeTo("ReferrersTarg", "bkpt", "()V");
	} else {
	// Let debuggee run for awhile to get classes loaded
	vm().resume();
	try {
	System.err.println("Press <enter> to continue");
	System.in.read();
	System.err.println("running...");

	} catch(Exception e) {
	}
	vm().suspend();
	}

	// Get all classes.
	long start = System.currentTimeMillis();
	List<ReferenceType> allClasses = vm().allClasses();
	long end = System.currentTimeMillis();
	System.out.println( allClasses.size() +
	" classes from vm.allClasses() took " +
	(end - start) + " ms");

	long[] counts;

	// Test for NPE
	{
	boolean pass = false;
	try {
	counts = vm().instanceCounts(null);
	} catch (NullPointerException ee) {
	pass = true;
	}
	if (!pass) {
	failure("failure: NullPointerException not thrown on instanceCounts(null)");
	}
	}

	// Test for 0 length array
	{
	List<ReferenceType>someClasses = new ArrayList(2);
	counts = vm().instanceCounts(someClasses);
	if (counts.length != 0) {
	failure("failure: instanceCounts with a zero length array fails: " +
	counts.length);
	}
	}

	// Test various values of maxInstances
	if (targetClass.name().equals("ReferrersTarg")) {
	List<ObjectReference> noInstances = targetClass.instances(0);
	if (noInstances.size() != ReferrersTarg.TARG_COUNT + 1) {
	failure("failure: instances(0): " + noInstances.size() + ", for " + targetClass);
	}
	noInstances = targetClass.instances(1);
	if (noInstances.size() != 1) {
	failure("failure: instances(1): " + noInstances.size() + ", for " + targetClass);
	}
	boolean pass = false;
	try {
	noInstances = targetClass.instances(-1);
	} catch (IllegalArgumentException ee) {
	pass = true;
	}
	if (!pass) {
	failure("failure: instances(-1) did not get an exception");
	}
	}

	// Instance counts for all classes
	start = System.currentTimeMillis();
	counts = vm().instanceCounts(allClasses);
	end = System.currentTimeMillis();

	if (counts.length == 0) {
	System.out.println("failure: No instances found");
	throw new Exception("ReferrersTest: failed");
	}

	// Create a list of ReferenceTypes sorted by instance count
	int size = 0;
	List<ToSort> sorted = new ArrayList(allClasses.size());
	for (int ii = 0; ii < allClasses.size(); ii++) {
	size += counts[ii];
	ToSort tos = new ToSort(counts[ii], allClasses.get(ii));
	sorted.add(tos);
	}

	System.out.println("instance counts for " + counts.length +
	" classes got " + size + " instances and took " +
	(end - start) + " ms");


	boolean gotReferrersFiller = false;
	boolean gotReferrersTarg = false;

	Collections.sort(sorted);
	for (int ii = sorted.size() - 1; ii >= 0 ; ii--) {
	ToSort xxx = sorted.get(ii);

	if (xxx.rt.name().equals("ReferrersFiller") &&
	xxx.count == ReferrersFiller.FILLER_COUNT) {
	gotReferrersFiller = true;
	}
	if (xxx.rt.name().equals("ReferrersTarg") &&
	xxx.count == ReferrersTarg.TARG_COUNT + 1) {
	gotReferrersTarg = true;
	}
	}
	if (!gotReferrersFiller) {
	failure("failure: Expected " + ReferrersFiller.FILLER_COUNT +
	" instances of ReferrersFiller");
	}
	if (!gotReferrersTarg) {
	failure("failure: Expected " + (ReferrersTarg.TARG_COUNT + 1) +
	" instances of ReferrersTarg");
	}

	List<List<ObjectReference>> allInstances = new ArrayList(10);

	// Instances, one class at a time, in sorted order, printing each line
	if (true) {
	System.out.println("\nGetting instances for one class " +
	"at a time (limited) in sorted order");
	List<ReferenceType> rtList = new ArrayList(1);
	rtList.add(null);
	long start1 = System.currentTimeMillis();
	size = 0;
	long count = 0;
	for (int ii = sorted.size() - 1; ii >= 0 ; ii--) {
	ToSort xxx = sorted.get(ii);
	if (xxx.count <= CUT_OFF) {
	break;
	}
	rtList.set(0, xxx.rt);
	start = System.currentTimeMillis();
	List<ObjectReference> oneInstances = xxx.rt.instances(19999999);
	end = System.currentTimeMillis();
	size += oneInstances.size();
	count++;
	System.out.println("Expected " + xxx.count + " instances, got " +
	oneInstances.size() +
	" instances for " + sorted.get(ii).rt +
	" in " + (end - start) + " ms");

	if (xxx.rt.name().equals("ReferrersFiller") &&
	oneInstances.size() != ReferrersFiller.FILLER_COUNT) {
	failure("failure: Expected " + ReferrersFiller.FILLER_COUNT +
	" instances of ReferrersFiller");
	}
	if (xxx.rt.name().equals("ReferrersTarg") &&
	oneInstances.size() != ReferrersTarg.TARG_COUNT + 1) {
	failure("failure: Expected " + (ReferrersTarg.TARG_COUNT + 1) +
	" instances of ReferrersTarg");
	}
	allInstances.add(oneInstances);
	}

	end = System.currentTimeMillis();

	System.out.println(size + " instances via making one vm.instances" +
	" call for each of " + count +
	" classes took " + (end - start1) + " ms");
	System.out.println("Per class = " +
	(end - start) / allClasses.size() + " ms");
	}


	// referrers

	// Test various values of maxReferrers
	if (targetClass.name().equals("ReferrersTarg")) {
	Field field1 = targetClass.fieldByName("theReferrersTarg");
	ObjectReference anInstance = (ObjectReference)targetClass.getValue(field1);
	List<ObjectReference> noReferrers = anInstance.referringObjects(0);
	if (noReferrers.size() != ReferrersTarg.TARG_COUNT + 1 ) {
	failure("failure: referringObjects(0) got " + noReferrers.size() +
	", for " + anInstance);
	}
	noReferrers = anInstance.referringObjects(1);
	if (noReferrers.size() != 1 ) {
	failure("failure: referringObjects(1) got " + noReferrers.size() +
	", for " + anInstance);
	}
	boolean pass = false;
	try {
	noReferrers = anInstance.referringObjects(-1);
	} catch (IllegalArgumentException ee) {
	pass = true;
	}
	if (!pass) {
	failure("failure: referringObjects(-1) did not get an exception");
	}
	}

	List<ObjectReference> allReferrers = null;
	List<ObjectReference> someInstances = new ArrayList();
	if (targetName.equals("ReferrersTarg")) {
	Field field1 = targetClass.fieldByName("theReferrersTarg");
	ObjectReference val = (ObjectReference)targetClass.getValue(field1);
	someInstances.add(val);
	allReferrers = val.referringObjects(99999); //LIMIT
	if (allReferrers.size() != ReferrersTarg.TARG_COUNT + 1) {
	failure("failure: expected " + (ReferrersTarg.TARG_COUNT + 1) +
	"referrers, but got " + allReferrers.size() +
	" referrers for " + val);
	}
	} else {
	// referrers
	// Create someInstances to find the referrers of.
	for (int ii = 0; ii < allClasses.size(); ii++) {
	List<ObjectReference> objRefList = allInstances.get(ii);
	if (objRefList != null) {
	int asize = objRefList.size();
	if (false) {
	System.out.println(asize + ", " + allClasses.get(ii));
	}
	// Remember one instance per class to get referrers
	if (asize > 0) {
	someInstances.add(objRefList.get(0));
	}
	}
	}
	}

	for (ObjectReference objRef: someInstances) {
	//System.out.println( "Getting referrers for " + objRef);
	start = System.currentTimeMillis();
	if ( true) {
	showReferrers(objRef, 0, 0, 0);
	} else {
	allReferrers = objRef.referringObjects(99999); //LIMIT
	end = System.currentTimeMillis();
	if (true \|\| allReferrers.size() > 1) {
	System.out.println( allReferrers.size() + " referrers for " + objRef + " took " + (end - start) + " ms");
	}
	}
	}

	/*
	* deal with results of test
	* if anything has called failure("foo") testFailed will be true
	*/
	if (!testFailed) {
	println("ReferrersTest: passed");
	} else {
	throw new Exception("ReferrersTest: failed");
	}
	}
	void indent(int level) {
	for (int ii = 0; ii < level; ii++) {
	System.out.print(" ");
	}
	}


	Map<ObjectReference, Object> visited = new HashMap(100);
	void showReferrers(ObjectReference objRef, int level, int total, int which) {

	if (level == 0) {
	visited.clear();
	} else {
	if (visited.containsKey(objRef)) {
	indent(level);
	System.out.println("(" + which + ")" + ":<pruned> " + objRef);
	return;
	}
	visited.put(objRef, null);
	indent(level);
	//System.out.println(which + "/" + total + ": " + objRef + " took " + time + " ms");
	}

	List<ObjectReference> allReferrers = null;

	//System.out.println( "Getting referrers for " + objRef);
	long start, end;
	start = System.currentTimeMillis();
	allReferrers = objRef.referringObjects(99999); //LIMIT
	end = System.currentTimeMillis();

	if (which == 0) {
	System.out.println(allReferrers.size() + " referrers for " + objRef + " took " + (end - start) + " ms");
	} else {
	System.out.println("(" + which + ") " + objRef);
	indent(level);
	System.out.println(" " + allReferrers.size() + " referrers for " + objRef + " took " + (end - start) + " ms");
	}

	// We have to stop going up a referrer chain in some cases
	Type rt = objRef.type();
	if (rt instanceof ClassType) {
	ClassType ct = (ClassType)rt;
	String name = ct.name();
	if (name.equals("sun.awt.SoftCache$ValueCell")) {
	return;
	}
	if (name.equals("java.lang.ref.Finalizer")) {
	return;
	}
	if (name.equals("java.lang.ref.SoftReference")) {
	return;
	}
	// oh oh, should really check for a subclass of ClassLoader :-)
	if (name.indexOf("ClassLoader") >= 0) {
	return;
	}
	// No doubt there are other reasons to stop ...
	}
	int itemNumber = 1;
	int allSize = allReferrers.size();
	for (ObjectReference objx: allReferrers) {
	showReferrers(objx, level + 1, allSize, itemNumber++);
	}
	}
	}