关于数组new 与不new 的问题

public class Test {

? String c;
? String b[][]?;

??String?d[][] = ?new String[][]{{"1","2"},{"3","4"}}; //一定可以，因为数组是引用类型
??public void a(){
????? ?b = {{"1","2"},{"3","4"}} //为什么就不行呢?

?????? String?e[][] = ?new String[][]{{"1","2"},{"3","4"}}; //一定可以，因为数组是引用类型

?????? c="1";
?}