public static void notEmpty(Collection<?> c,String name){
  notNull(c,name);
  if (c.isEmpty())   throw new IllegalArgumentException(INVALID_ARG_MSG_PREFIX + name + NOT_EMPTY_SUFFIX);
}

public static void notEmpty ( Collection < ? > c , String name ) { notNull ( c , name ) ; if ( c . isEmpty ( ) ) throw new IllegalArgumentException ( INVALID_ARG_MSG_PREFIX + name + NOT_EMPTY_SUFFIX ) ; }
checks that given collection is not empty .
