❌ IllegalStateException：Method Has Been Invoked at an Illegal or Inappropriate Time 的完美解决方法 ❌

List<String> list = new ArrayList<>();
list.add("Hello");
list.add("World");
Iterator<String> iterator = list.iterator();
iterator.next(); // 正常调用
iterator.remove(); // IllegalStateException: remove() must be called after next()

if (iterator.hasNext()) {
    String element = iterator.next();
    // 进行操作
    iterator.remove(); // 正确的调用顺序
}

enum State {
    INITIAL, RUNNING, COMPLETED
}

class MyClass {
    private State state = State.INITIAL;

    public void start() {
        if (state != State.INITIAL) {
            throw new IllegalStateException("不能在当前状态启动！");
        }
        state = State.RUNNING;
    }

    public void complete() {
        if (state != State.RUNNING) {
            throw new IllegalStateException("必须在运行状态完成！");
        }
        state = State.COMPLETED;
    }
}

if (state == State.RUNNING) {
    // 执行操作
} else {
    throw new IllegalStateException("当前状态不允许执行该操作！");
}

catch (IllegalStateException e) {
    logger.error("方法调用顺序错误：", e);
}