Can't a switch use final parameters?

[Jeff Bosch]

I tried building a method with a configurable switch statement, to test how method-local parameters and variables work when declared final. A switch statement needs constant expressions for the case statement, and the final local variables/parameters are constant. Do I get a compiler error because the case labels are potentially not constant at compile time?
Here are relevant snippets of the code:

    // method declaration
    static int testFinal( final int x, final int y, final int z, int arg ){
        System.out.print( "Arg = " );
        switch( arg ){
            case x: System.out.println( x ); return x;
            case y: System.out.println( y ); return y;
            case z: System.out.println( z ); return z;
            default: System.out.println( "no known value" ); return -1;
        }
    }
    // calling code
    // Test: Can a final parameter act as a contant for a switch() 
    //       statement?
    int result1 = testFinal( int2[0], int2[1], int2[2], 35 );
    int result2 = testFinal( int2[0], int2[1], int2[2], 22 );
    if ( result1 > 0 )
    {
        // The if results could go into a method for efficiency
        System.out.println( "\nResults okay: result1 = " + result1 + "!" );
    } else {
        System.out.println( "\nSorry! Result not found...\n" );
    }
    if ( result2 > 0 )
    {
        System.out.println( "\nResults okay: result2 = " + result2 + "!" );
    } else {
        System.out.println( "\nSorry! Result not found...\n" );
    }

I even tried assigning a value to a local final variable through the parameters:

  static int testFinal( final int x, final int y,  final int z, int arg ){
    final int myX = x;
    System.out.print( "Arg = " );
    switch( arg ){
      case myX: System.out.println( myX ); return myX;
      case y: System.out.println( y ); return y;
      case z: System.out.println( z ); return z;
      default: System.out.println( "no known value" ); return -1;
    }
  }

But I had the same error in both cases:

---------- Compiler ----------
ArrayTester.java:56: constant expression required
case myX: System.out.println( myX ); return myX;
                             ^
ArrayTester.java:57: constant expression required
case y: System.out.println( y ); return y;
                             ^
ArrayTester.java:58: constant expression required
case z: System.out.println( z ); return z;
                             ^
3 errors
Normal Termination
Output completed (4 sec consumed).

Is this because these final varables must be declared and initialized before compilation? I thought the answer was 'no' because you can initialize final variables through constructors with no problem. But my results tell me that I don't really understand when a final variable is a constant and when it's not. Note that assigning a local value to one of the final variables removes the compiler error: final int x = 2;
Any help?
Thanks!
Regards,
Jeff

[Barry Gaunt]

Jeff, the thing after the case must be a ConstantExpression as in The Java Language Specification paragraph 15.8
So anything which is a formal parameter to a method is a "no-no".

[Jeff Bosch]

Thanks, Barry.
I found the answer this morning and was hoping I could post a "nevermind" message before anyone took the time to respond!
Regards,
Jeff