private static void forceInit(Class<?> cls){
  try {
    Class.forName(cls.getName(),true,cls.getClassLoader());
  }
 catch (  ClassNotFoundException e) {
    throw new IllegalArgumentException("Can't initialize class " + cls,e);
  }
}

private static void forceInit ( Class < ? > cls ) { try { Class . forName ( cls . getName ( ) , true , cls . getClassLoader ( ) ) ; } catch ( ClassNotFoundException e ) { throw new IllegalArgumentException ( "Can't initialize class " + cls , e ) ; } }
force initialization of the static members . as of java 5 , referencing a class doesn ' t force it to initialize . since this class requires that the classes be initialized to declare their comparators , we force that initialization to happen .
