valueOf methods of Short, Integer and Long

This is a very interesting, in the JDK implementation,
any number between -128 and 127, the JDK create a cache :

  
static class valueOfCache {
/**
 * A cache of instances used by {@link Integer#valueOf(int)}
 * and auto-boxing.
 */

 static final Integer[] CACHE = new Integer[256];
 static {
    for(int i=-128; i<=127; i++) {                        
       CACHE[i+128] = new Integer(i);       
    } 
 } 
} 

And the static valueOf() method:

 
/*If it is not necessary to get a new {@code Integer}
*instance,it is recommended to use this method instead
*of the constructor,since it maintains a cache of
*instances which may result in better performance.
*/
public static Integer valueOf(int i) {  
    if (i < -128 || i > 127) {
       return new Integer(i);
    }
    return valueOfCache.CACHE [i+128];
}

Sometime this method gives a better performance,
but there are a lot of debates here.