java - 下面类的线程安全是否会被破坏？我确信不可能，但只是想双重确定，因为它不容易测试

Question

public class ThreadSafe implements ITaskCompletionListener {

private final Set<String> taskIds = new HashSet<String>();
private final Set<String> successfulIds = new HashSet<String>();
private final Set<String> cancelledIds = new HashSet<String>();
private final Set<String> errorIds = new HashSet<String>();

public ThreadSafe() {

}

// invoked concurrently
@Override
public void onCancel(String pTaskId) {
    remove(pTaskId);
    cancelledIds.add(pTaskId);
}

// invoked concurrently
@Override
public void onError(String pTaskId) {
    remove(pTaskId);
    errorIds.add(pTaskId);
}

// invoked concurrently
@Override
public void onSuccess(String pTaskId) {
    remove(pTaskId);
    successfulIds.add(pTaskId);
}

private void remove(String pTaskId) {
    taskIds.remove(pTaskId);
}

}

Answer 1

来自HashSet文档:

Note that this implementation is not synchronized. If multiple threads access a hash set concurrently, and at least one of the threads modifies the set, it must be synchronized externally

所以不，你的代码不是线程安全的。并发访问任何方法都可能会产生奇怪的结果。