2～4

int address = System. identityHashCode（a）;

System, out. printf （"数组 a 的引用 % x\n",address）;

address = System.identityHashCode（b）;

System, out. printf（"数组 b 的引用 % x\n",address）;

System, out. println（"将 b 的值赋值给 a"）;

a = b; 〃将b的值赋值给a

address = System. identityHashCode（a）;

System, out. printf （"数组 a 的引用％ x\n"z address）;

address = System. identityHashCode（b）;

System, out. printf （"数组 b 的引用 % x\n",address）;

System, out. println（a == b）;

System, out. println（"数组 a 的元素个数="+ a. length）;

System, out. println（"数组 b 的元素个数="+ b. length）；

System.out. println（"a[0] = " + a[0] + ",a[l]

System, out. print（"b[0] = " + b[0] + *'zb[l]=