Java ThreadFactory 如何创建 ThreadCreationException 以在 JUnit 中进行测试

Question

尝试使用 ThreadFactory 创建单元测试(边界集成测试)，只是想知道如何“强制”Java/JVM 无法创建更多线程？

换句话说，我如何调用 ThreadFactory.newThread 并获取 null ？

import org.jboss.threads.JBossThreadFactory.JBossThreadFactory;  
import java.util.concurrent.ThreadFactory;

private final ThreadFactory threadFactory;

JBossThreadFactory threadFactory = new JBossThreadFactory(null, null, null, "test thread %p %t", null, null);

final Thread thread = threadFactory.newThread(new Worker(task));
if (thread == null) {
    throw new ThreadCreationException();
}

Answer 1

如果您使用依赖注入(inject)，那么您可以创建一个模拟ThreadFactory:

private class NullThreadFactory implements ThreadFactory {
    public Thread newThread(Runnable r) {
        return null;
    }
}

并注入(inject)使用 NullThreadFactory 而不是 JBossThreadFactory 来进行特定的单元测试。