Re: RFR: 8039432 demo/jvmti/mtrace/TraceJFrame.java can't connect to X11

[shanliang]

Hi Staffan,

I did work on this bug and I thought the problem was from a bad DISPLAY 
setting (see my comments in the bug), I might miss something here.

I looked at the class GraphicsEnvironment.java, 
getLocalGraphicsEnvironment() calls createGE(), and the latter has the 
following code:

           Class<GraphicsEnvironment> geCls;
            ......
           ge = geCls.newInstance();
//          long t1 = System.currentTimeMillis();
//          System.out.println("GE creation took " + (t1-t0)+ "ms.");
           if (isHeadless()) {
               ge = new HeadlessGraphicsEnvironment(ge);
           }

so we should not get an AWTError in case of headless, instead we get a 
HeadlessGraphicsEnvironment.

Look at the following 2 methods:

   public static boolean isHeadless() {
       return getHeadlessProperty();
   }

   public boolean isHeadlessInstance() {
       // By default (local graphics environment), simply check the
       // headless property.
       return getHeadlessProperty();
   }

it seems no difference to call
   GraphicsEnvironment.getLocalGraphicsEnvironement().isHeadlessInstance()
and
   GraphicsEnvironment.isHeadless()   

yes better to cal the static method, but I am not sure that the direct 
call would fix the failure.

Thanks,
Shanliang


Staffan Larsen wrote:
This test causes exceptions that looks like this:

java.awt.AWTError: Can't connect to X11 window server using ‘REDACTED:503' as 
the value of the DISPLAY variable.
        at sun.awt.X11GraphicsEnvironment.initDisplay(Native Method)
        at 
sun.awt.X11GraphicsEnvironment.access$200(X11GraphicsEnvironment.java:65)
        at sun.awt.X11GraphicsEnvironment$1.run(X11GraphicsEnvironment.java:115)
        at java.security.AccessController.doPrivileged(Native Method)
        at 
sun.awt.X11GraphicsEnvironment.<clinit>(X11GraphicsEnvironment.java:74)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:259)
        at java.awt.GraphicsEnvironment.createGE(GraphicsEnvironment.java:102)
        at 
java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment(GraphicsEnvironment.java:81)
        at TraceJFrame.main(TraceJFrame.java:39)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at 
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at 
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:484)
        at 
com.sun.javatest.regtest.MainAction$SameVMRunnable.run(MainAction.java:754)
        at java.lang.Thread.run(Thread.java:744)


The fix seems to be to not call 
GraphicsEnvironment.getLocalGraphicsEnvironement().isHeadlessInstance() but 
GraphicsEnvironment.isHeadless() directly.

Please review the fix below,

Thanks,
/Staffan



diff --git a/test/demo/jvmti/mtrace/TraceJFrame.java 
b/test/demo/jvmti/mtrace/TraceJFrame.java
--- a/test/demo/jvmti/mtrace/TraceJFrame.java
+++ b/test/demo/jvmti/mtrace/TraceJFrame.java
@@ -36,7 +36,7 @@

 public class TraceJFrame {
     public static void main(String args[]) throws Exception {
-        if 
(GraphicsEnvironment.getLocalGraphicsEnvironment().isHeadlessInstance()) {
+        if (GraphicsEnvironment.isHeadless()) {
             System.out.println("JFrame test was skipped due to headless mode");
         } else {
             DemoRun demo;