我正在寻找EDT关闭而不是重启的可能原因。 更具体的是，我有一个测试套件，偶尔其中一个测试会因超时而受到影响。线程转储总是非常类似于以下（我从主线程中删除了一些不相关的行）：
Full thread dump Java HotSpot(TM) 64-Bit Server VM (24.79-b02 mixed mode):
"Attach Listener" daemon prio=10 tid=0x00007f7c60001000 nid=0x5d0f runnable [0x0000000000000000]
java.lang.Thread.State: RUNNABLE
"main-SharedResourceRunner" daemon prio=10 tid=0x00007f7c908e6000 nid=0x5ce6 in Object.wait() [0x00007f7c8416a000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on <0x00000000eed580f0> (a jogamp.opengl.SharedResourceRunner)
at java.lang.Object.wait(Object.java:503)
at jogamp.opengl.SharedResourceRunner.run(SharedResourceRunner.java:252)
- locked <0x00000000eed580f0> (a jogamp.opengl.SharedResourceRunner)
at java.lang.Thread.run(Thread.java:745)
"AWT-XAWT" daemon prio=10 tid=0x00007f7c9085d000 nid=0x5ce3 runnable [0x00007f7c8456e000]
java.lang.Thread.State: RUNNABLE
at sun.awt.X11.XToolkit.waitForEvents(Native Method)
at sun.awt.X11.XToolkit.run(XToolkit.java:541)
at sun.awt.X11.XToolkit.run(XToolkit.java:505)
at java.lang.Thread.run(Thread.java:745)
"Java2D Disposer" daemon prio=10 tid=0x00007f7c90840800 nid=0x5ce2 in Object.wait() [0x00007f7c8466f000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on <0x00000000eee2f878> (a java.lang.ref.ReferenceQueue$Lock)
at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:135)
- locked <0x00000000eee2f878> (a java.lang.ref.ReferenceQueue$Lock)
at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:151)
at sun.java2d.Disposer.run(Disposer.java:145)
at java.lang.Thread.run(Thread.java:745)
"Service Thread" daemon prio=10 tid=0x00007f7c9009b800 nid=0x5cdc runnable [0x0000000000000000]
java.lang.Thread.State: RUNNABLE
"C2 CompilerThread1" daemon prio=10 tid=0x00007f7c90099800 nid=0x5cdb waiting on condition [0x0000000000000000]
java.lang.Thread.State: RUNNABLE
"C2 CompilerThread0" daemon prio=10 tid=0x00007f7c90096800 nid=0x5cda waiting on condition [0x0000000000000000]
java.lang.Thread.State: RUNNABLE
"Signal Dispatcher" daemon prio=10 tid=0x00007f7c90094000 nid=0x5cd9 runnable [0x0000000000000000]
java.lang.Thread.State: RUNNABLE
"Finalizer" daemon prio=10 tid=0x00007f7c90072000 nid=0x5cd8 in Object.wait() [0x00007f7c94e73000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on <0x00000000eee34650> (a java.lang.ref.ReferenceQueue$Lock)
at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:135)
- locked <0x00000000eee34650> (a java.lang.ref.ReferenceQueue$Lock)
at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:151)
at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:209)
"Reference Handler" daemon prio=10 tid=0x00007f7c90070000 nid=0x5cd7 in Object.wait() [0x00007f7c94f74000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on <0x00000000eedcc110> (a java.lang.ref.Reference$Lock)
at java.lang.Object.wait(Object.java:503)
at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:133)
- locked <0x00000000eedcc110> (a java.lang.ref.Reference$Lock)
"main" prio=10 tid=0x00007f7c9000c000 nid=0x5cd1 in Object.wait() [0x00007f7c99c20000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on <0x00000000eb3adf98> (a java.awt.EventQueue$1AWTInvocationLock)
at java.lang.Object.wait(Object.java:503)
at java.awt.EventQueue.invokeAndWait(EventQueue.java:1282)
- locked <0x00000000eb3adf98> (a java.awt.EventQueue$1AWTInvocationLock)
at java.awt.EventQueue.invokeAndWait(EventQueue.java:1263)
"VM Thread" prio=10 tid=0x00007f7c9006b800 nid=0x5cd6 runnable
"GC task thread#0 (ParallelGC)" prio=10 tid=0x00007f7c90022000 nid=0x5cd2 runnable
"GC task thread#1 (ParallelGC)" prio=10 tid=0x00007f7c90023800 nid=0x5cd3 runnable
"GC task thread#2 (ParallelGC)" prio=10 tid=0x00007f7c90025800 nid=0x5cd4 runnable
"GC task thread#3 (ParallelGC)" prio=10 tid=0x00007f7c90027800 nid=0x5cd5 runnable
"VM Periodic Task Thread" prio=10 tid=0x00007f7c900ae800 nid=0x5cdd waiting on condition
JNI global references: 297
注意main线程如何使用EventQueue.invokeAndWait在EDT上安排某些事情，但线程转储中没有EDT。并且没有EDT意味着main线程将永远等待，因为Runnable永远不会终止。
在进行线程转储的那一刻，在EDT上已经安排了一些Runnable，这些都已成功运行或测试未达到此点。这表明EDT崩溃了，无法重新启动。
不幸的是，我没有代码可以重现这个问题。我甚至无法在我自己的开发机器上重现这个问题，而这个测试有时会遇到问题。我甚至很难在CI上复制这个，因为它似乎每隔几百次就会超时一次。
我正在寻找可能导致此行为的建议，或者我可以做些什么来调查此问题并稳定我的测试。我最好的猜测是异常导致EDT崩溃，但即便如此，EDT应该恢复并且能够运行下一个Runnable发布到它，如下面的代码所示：
import java.awt.EventQueue;
import java.lang.reflect.InvocationTargetException;
public class Test {
public static void main(String[] args) throws InvocationTargetException, InterruptedException {
try {
EventQueue.invokeAndWait(new Runnable() {
@Override
public void run() {
throw new RuntimeException("exception");
}
});
} catch (Exception e) {
//ignore
}
EventQueue.invokeAndWait(
new Runnable() {
@Override
public void run() {
System.out.println("EDT restarted");
}
}
);
System.out.println("All runnables finished");
}
}
请注意，我的测试在EDT或任何其他线程上没有设置特殊UncaughtExceptionHandler，也没有替换默认的UncaughtExceptionHandler。我甚至不确定EDT是否有例外。当系统超时时，CI系统会丢失System.err和System.out输出。我只有线程转储可用。
修改
我担心这个问题不是100％清楚。我的测试代码看起来像
@Test
public void testSomethingWhichInteractsWithTheEDT(){
doStuffOnMainThread();
//do or check something on the EDT
EventQueue.invokeAndWait( new Runnable(){...});
doMoreStuffOnMainThread();
//do or check something else on the EDT
EventQueue.invokeAndWait( new Runnable(){...});
}
偶尔会有其中一个
EventQueue.invokeAndWait( new Runnable(){...});
主线程上的调用将无限期地阻塞，并且在该点进行的线程转储将不再显示"AWT-EventQueue-0"实例。
虽然测试使用Swing组件，但它们永远不会显示，也不会添加到顶级组件中。为简单起见，假设我创建JPanel但从未将其添加到JFrame。
这意味着：
Runnable安排我要在EDT上执行的invokeAndWait个Runnable。在这两者之间，EDT很可能因为没有可见的顶级组件而没有待处理的事件而关闭，并且下一个EventQueue#invokeAndWait在＆＃34; new＆＃34;上执行。 EDT。但据我所知，这并不违反任何与Swing相关的并发规则。我在正确的线程上安排所有操作，并且规则中没有提到在程序运行期间始终保持顶级组件可见，以保持相同的EDT存活。 EDT被替换的事实（也可能由于异常as discussed here而发生）AFAIK不会阻止任何后续Node.childNodes次呼叫。
答案 0 :(得分：2)
@mKorbel不确定你的意思，但在那个特定的测试中我没有可见的顶级组件。我有Swing组件，但从未将它们放在顶级组件中，也不让它们可见
@Robin
invokeAndWait应始终针对EventQueue.isDispatchThread / SwingUtilities.isEventDispatchThread进行测试，以避免RepaintManager 例如
import java.awt.EventQueue;
import java.awt.TextField;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.concurrent.*;
import javax.swing.*;
public class IsThereEDT {
private ScheduledExecutorService scheduler;
private AccurateScheduledRunnable periodic;
private ScheduledFuture<?> periodicMonitor;
private int taskPeriod = 30;
private SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");
private Date dateRun;
public IsThereEDT() {
scheduler = Executors.newSingleThreadScheduledExecutor();
periodic = new AccurateScheduledRunnable() {
private final int ALLOWED_TARDINESS = 200;
private int countRun = 0;
private int countCalled = 0;
@Override
public void run() {
countCalled++;
if (this.getExecutionTime() < ALLOWED_TARDINESS) {
countRun++;
isThereReallyEDT(); // non on EDT
}
}
};
periodicMonitor = scheduler.scheduleAtFixedRate(periodic, 0, taskPeriod, TimeUnit.SECONDS);
periodic.setThreadMonitor(periodicMonitor);
isThereReallyEDT();
//TextField text = new TextField();
//JFrame frame1 = new JFrame("Frame 1");
/*SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
isThereReallyEDT();
JFrame frame1 = new JFrame("Frame 1");
frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame1.getContentPane().add(new JLabel("Hello in frame 1"));
frame1.pack();
frame1.setLocation(100, 100);
frame1.setVisible(true);
}
});*/
/*SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
JFrame frame2 = new JFrame("Frame 2");
frame2.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame2.getContentPane().add(new JLabel("Hello in frame 2"));
frame2.pack();
frame2.setLocation(200, 200);
frame2.setVisible(true);
isThereReallyEDT();
}
});*/
isThereReallyEDT();
}
private void isThereReallyEDT() {
dateRun = new java.util.Date();
System.out.println(" Time at : " + sdf.format(dateRun));
if (EventQueue.isDispatchThread()) {
System.out.println("Calling from EventQueue.isDispatchThread");
} else {
System.out.println("There isn't Live EventQueue.isDispatchThread, why any reason for that ");
}
if (SwingUtilities.isEventDispatchThread()) {
System.out.println("Calling from SwingUtilities.isEventDispatchThread");
} else {
System.out.println("There isn't Live SwingUtilities.isEventDispatchThread, why any reason for that ");
}
System.out.println();
}
public static void main(String[] args) {
IsThereEDT isdt = new IsThereEDT();
/*SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
JFrame frame = new JFrame();
frame.setVisible(true);
try {
Thread.sleep(1000);
} catch (Exception e) {
}
frame.dispose();
JOptionPane.showMessageDialog(frame, "Test case 1, "
+ "JVM won't terminate.");
}
});*/
}
}
abstract class AccurateScheduledRunnable implements Runnable {
private ScheduledFuture<?> thisThreadsMonitor;
public void setThreadMonitor(ScheduledFuture<?> monitor) {
this.thisThreadsMonitor = monitor;
}
protected long getExecutionTime() {
long delay = -1 * thisThreadsMonitor.getDelay(TimeUnit.MILLISECONDS);
return delay;
}
}
具有正确和良好的输出（没有显示顶级容器至少一次（真的）可见到屏幕）
Time at : 11:03:50 There isn't Live EventQueue.isDispatchThread, why any reason for that There isn't Live SwingUtilities.isEventDispatchThread, why any reason for that
Time at : 11:04:20 There isn't Live EventQueue.isDispatchThread, why any reason for that There isn't Live SwingUtilities.isEventDispatchThread, why any reason for that
Time at : 11:04:50 There isn't Live EventQueue.isDispatchThread, why any reason for that There isn't Live SwingUtilities.isEventDispatchThread, why any reason for that