One of the difference between JDK1.6.0 and JDK1.7.0

1. The test java code:

package com.haowei.oom;
import com.haowei.Util;
import java.util.ArrayList;
public class OOM {
    public static void stringInternOOM(){
        int counter = 1;
        try{
            int max = Integer.MAX_VALUE;
            ArrayList list = new ArrayList();
            for(int i=0;i<max;i++){
                String str = String.valueOf(i);
                list.add(str.intern());
                counter++;
            }
        }catch(Exception e){
            e.printStackTrace();
        }finally{
            Util.log("the max String.Intern counter = " + counter);
        }
    }
    
    public static void main(String args[]){
        stringInternOOM();
    }
}

2. The execute script:

java -cp . -Xms16m -Xmx16m -XX:PermSize=16m -XX:MaxPermSize=16m com/haowei/oom/OOM

3. The result of JDK1.6.0

*********version begin****************
Apache Ant(TM) version 1.8.2 compiled on December 20 2010
java version "1.6.0_26"
Java(TM) SE Runtime Environment (build 1.6.0_26-b03)
Java HotSpot(TM) Client VM (build 20.1-b02, mixed mode, sharing)
*********version end****************

*************** begin to run java ***************

the max String.Intern counter = 348980
Exception in thread "main" java.lang.OutOfMemoryError: PermGen space
	at java.lang.String.intern(Native Method)
	at com.haowei.oom.OOM.stringInternOOM(Unknown Source)
	at com.haowei.oom.OOM.main(Unknown Source)

 4.The result of JDK1.7.0

*********version begin****************
Apache Ant(TM) version 1.8.2 compiled on December 20 2010
openjdk version "1.7.0-internal-debug"
OpenJDK Runtime Environment (build 1.7.0-internal-debug-haowei_2012_02_06_22_42-b00)
OpenJDK Client VM (build 21.0-b17-jvmg, mixed mode)
*********version end****************

*************** begin to run java ***************

the max String.Intern counter = 304460
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
	at java.lang.Integer.toString(Integer.java:333)
	at java.lang.String.valueOf(String.java:3007)
	at com.haowei.oom.OOM.stringInternOOM(Unknown Source)
	at com.haowei.oom.OOM.main(Unknown Source)
VM option 'PermSize=16m'
VM option 'MaxPermSize=16m'