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import java.util.ArrayList;
import java.util.List;

public class Test {
    static class OOMObject {

    }
    public static void main(String[] args) {
        List<OOMObject> list = new ArrayList<OOMObject>();
        while(true){
            list.add(new OOMObject());
        }
    }
}

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baoguo@MacBook-Pro java % java -Xms20m -Xmx20m -XX:+HeapDumpOnOutOfMemoryError Test
java.lang.OutOfMemoryError: Java heap space
Dumping heap to java_pid9597.hprof ...
Heap dump file created [27555334 bytes in 0.085 secs]
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
	at java.util.Arrays.copyOf(Arrays.java:3210)
	at java.util.Arrays.copyOf(Arrays.java:3181)
	at java.util.ArrayList.grow(ArrayList.java:265)
	at java.util.ArrayList.ensureExplicitCapacity(ArrayList.java:239)
	at java.util.ArrayList.ensureCapacityInternal(ArrayList.java:231)
	at java.util.ArrayList.add(ArrayList.java:462)
	at Test.main(Test.java:11)
  

  
baoguo@MacBook-Pro java % jhat -port 7401 -J-Xmx4G java_pid9597.hprof
baoguo@MacBook-Pro ~ % jconsole