当索引以数组大小为模时,是否有可能使索引超出约束？

Question

我有以下代码,但有时我会得到java.lang.ArrayIndexOutOfBoundsException特定的代码subject.gets.我不知道这怎么会发生,但它只是做到了.我有一些多线程,但这个数组是函数的本地数据,不能从其他任何地方访问.

// Within onCreate
Random random = new Random();

// some where else
List<Subject> subjects = new ArrayList<Subject>();

// There is SOME CODE HERE TO ADD ELEMENTS.
// There is SOME CODE HERE TO ADD ELEMENTS.
// There is SOME CODE HERE TO ADD ELEMENTS.
// There is SOME CODE HERE TO ADD ELEMENTS.
// There is SOME CODE HERE TO ADD ELEMENTS.

subjects.get(random.nextInt() % subjects.size())

Answer 1

如果random.nextInt()返回负整数,则mod操作的结果将为负.

请参阅注释以了解可能的解