int [] a1 = new int[]{1,2,3}; 
  int [] a2 = new int[]{1,2,3,4}; 
  int [][] a3 = new int [][] {{1,2,3,4},{5,6,7,8}}; 
  String [] s4 = new String[]{"s1","s2","s3",}; 
  String [][] s5 = new String [][] {{"s1","s2","s3"},{"s4","s5","s6"}}; 
  Object[] obj = s5;                                     //这里为什么不对啊 ,听不懂 |