import java.util.IdentityHashMap;
import java.util.Map;
public class Main {
public static void main(String[] argv) throws Exception {
Map objMap = new IdentityHashMap();
Object o1 = new Integer(123);
Object o2 = new Integer(123);
objMap.put(o1, "first");
objMap.put(o2, "second");
Object v1 = objMap.get(o1); // first
Object v2 = objMap.get(o2); // second
}
}