我觉得这个do while是个死循环，flags里的任何元素申明时都是为false,进入do while后条件也是为false,那不会一直循环下去，求大神分析
char[] chs = new char[5];
char[] letters = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V',
'W', 'X', 'Y', 'Z' };
boolean[] flags = new boolean[letters.length];
for (int i = 0; i < chs.length; i++) {
int index;
do {
index = (int) (Math.random() * (letters.length));
} while (flags[index]);// 判断生成的字符是否重复
chs[i] = letters[index];
flags[index] = true;
}
return chs;
