@SuppressWarnings("unchecked") private static Class wrap(Class c){
  return c.isPrimitive() ? PRIMITIVES_TO_WRAPPERS.get(c) : c;
}

@ SuppressWarnings ( "unchecked" ) private static Class wrap ( Class c ) { return c . isPrimitive ( ) ? PRIMITIVES_TO_WRAPPERS . get ( c ) : c ; }
gets corresponding wrapper for a primitive type .
