why I can't rotate my md2 model?

[Davi]

before use world.addObject(md2); I want to let my model rotate 90 angle,
I use md2.rotateX(90);
or
   

Matrix ma=new Matrix();
      ma.rotateX(90);
      ma.rotateY(90);
      ma.rotateZ(90);
        snork.setRotationMatrix(ma);

But why it can't work???

[EgonOlsen]

Not in degrees, in radians. I.e. 90 should be Math.PI/2 instead.