Java 与 Groovy 继承和基于父类的线程上下文

Question

我正在使用 Groovy 2.4.7，并且遇到了意外的行为。让我们看一下这个简单的 Java 代码:

public class InheritanceBugTest {

    private class Parent {

        private volatile String h = "Hello world";
        private volatile String c;

        String getHello() throws InterruptedException {
            Thread t = new Thread(new Runnable() {
                public void run() {
                    c = h;
                }
            });
            t.start();
            t.join();
            return c;
        }
    }

    private class Child extends Parent {

        String getParentHello() throws InterruptedException {
            return getHello();
        }
    }

    public InheritanceBugTest() throws InterruptedException {
        Parent parent = new Parent();
        assert "Hello world".equals(parent.getHello());

        Child child = new Child();
        assert "Hello world".equals(child.getParentHello());
    }

    public static void main(String[] args) throws InterruptedException {

        new InheritanceBugTest();

    }   
}

这显然在 Java 中工作得很好。 现在介绍 Groovy:

class InheritanceBugTest extends Specification {

    private class Parent {

        private volatile String h = "Hello world";
        private volatile String c;

        String getHello() throws InterruptedException {
            Thread t = new Thread(new Runnable() {
                public void run() {
                    c = h;
                }
            });
            t.start();
            t.join();
            return c;
        }
    }

    private class Child extends Parent {

        String getParentHello() throws InterruptedException {
            return getHello();
        }
    }

    def 'test correct Parent behavior'() {

        given:
        def parent = new Parent()
        def hello

        when:
        hello = parent.getHello()

        then:
        hello == 'Hello world'
    }

    def 'test correct Child behavior'() {

        given:
        def child = new Child()
        def hello

        when:
        hello = child.getParentHello()

        then:
        hello == 'Hello world'
    }    
}

在这里，我最终第一个测试运行良好，第二个测试在 Exception in thread "Thread-2" groovy.lang.MissingPropertyException: No such property: h for class: org.codehaus.groovy.InheritanceBugTest 上失败。 .

看来 Groovy 线程在不同的上下文中运行，其中没有 h存在。这种行为正常还是错误？

Answer 1

看起来它已经打开了groovy bug https://issues.apache.org/jira/browse/GROOVY-5438 .

您可以通过将访问修饰符更改为“ protected ”来避免这种情况。