Assigning an object a primative value[ compiler magic | documented] ?

Question

I recently discovered something I was doing in code on J2SE (Mac & Sun) which I never recall knowing you could do. That is assigning an Object a primative an integral datatype, like a short. Example:
public class PrimativeTest {
    public static void main(String[] args) {
        Object sp = getShortPrimative();
        Object so = getShortObject();
        Object da = (short) 34;
        System.out.println("primative version value: " + sp.toString() + " type: " + sp.getClass().toString());
        System.out.println("object  version value: " + so.toString() + " type: " + so.getClass().toString());
        System.out.println("direct assignment version value: " + da.toString() + " type: " + da.getClass().toString());
    static short getShortPrimative() { return (short) 75; }
    static Short getShortObject() { return new Short((short) 25); }   
}Produces:
primative version value: 75 type: class java.lang.Short
object version value: 25 type: class java.lang.Short
direct assignment version value: 34 type: class java.lang.Short
Don't get me wrong, I am using this, like it, and now know I am using it. I, however, cannot find where this is declared as a feature. My concern stems from some of this code is to run on J2ME in the future. How many implementations of that are there?
Can someone please link me up with the on-line doc that say this is legal.
Thank you

Answer 1

Good points about compiler settings. Am using Netbeans with CVS. I literally needed a spreadsheet to plan out which project goes to which platform (servlet, desktop, phone) all in advance.
Figuring out how to compile, assemble (obfuscate/sign), & preverify (for J2ME) common code is one of the reasons I said 'in the future' of my orginal post.
Back in the 'old days', I used Visual Sourcesafe doing VB programming, so I keep trying to figure out a way to make CVS solve my problem. With sourcesafe, one project had the source, but you could put an alias to that file in other projects. I do not want branches that drift apart. If that worked, I could just make three actually distributed projects with all the classes each needed, one of which was compiled using the Mobility pack.
Not really a subject for this forum, but thought I would expand on the issue raised.