Fixed race condition issue when starting up GTK trays. Changed exectutor service to shutdown on removeTray

src/dorkbox/util/tray/SystemTray.java

@@ -12,7 +12,7 @@ import java.nio.charset.Charset;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.security.SecureRandom;
-import java.util.concurrent.Executor;
+import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 
 import org.slf4j.Logger;
@@ -77,7 +77,7 @@ public abstract class SystemTray  {
         }
     }
 
-    protected Executor callbackExecutor = Executors.newSingleThreadExecutor(new NamedThreadFactory("SysTrayExecutor", false));
+    protected ExecutorService callbackExecutor = Executors.newSingleThreadExecutor(new NamedThreadFactory("SysTrayExecutor", false));
 
     public volatile FailureCallback failureCallback;
     protected volatile boolean active = false;
@@ -110,7 +110,10 @@ public abstract class SystemTray  {
     }
 
     public abstract void createTray(String iconName);
-    public abstract void removeTray();
+
+    public void removeTray() {
+        SystemTray.this.callbackExecutor.shutdown();
+    }
 
     public abstract void setStatus(String infoString, String iconName);
 

src/dorkbox/util/tray/linux/AppIndicatorTray.java

@@ -4,6 +4,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.CountDownLatch;
 
 import com.sun.jna.Pointer;
 
@@ -31,7 +32,7 @@ public class AppIndicatorTray extends SystemTray {
     private static Gobject libgobject = Gobject.INSTANCE;
     private static Gtk libgtk = Gtk.INSTANCE;
 
-
+    private final CountDownLatch blockUntilStarted = new CountDownLatch(1);
     private final Map<String, MenuEntry> menuEntries = new HashMap<String, MenuEntry>(2);
 
     private volatile AppIndicator.AppIndicatorInstanceStruct appIndicator;
@@ -89,6 +90,9 @@ public class AppIndicatorTray extends SystemTray {
             this.gtkUpdateThread = new Thread() {
                 @Override
                 public void run() {
+                    // notify our main thread to continue
+                    AppIndicatorTray.this.blockUntilStarted.countDown();
+
                     try {
                         libgtk.gtk_main();
                     } catch (Throwable t) {
@@ -101,7 +105,12 @@ public class AppIndicatorTray extends SystemTray {
             this.gtkUpdateThread.start();
         }
 
-        this.active = true;
+        // we CANNOT continue until the GTK thread has started! (ignored if SWT is used)
+        try {
+            this.blockUntilStarted.await();
+            this.active = true;
+        } catch (InterruptedException e) {
+        }
     }
 
     @Override
@@ -132,6 +141,8 @@ public class AppIndicatorTray extends SystemTray {
         }
 
         this.connectionStatusItem = null;
+
+        super.removeTray();
     }
 
     @Override

src/dorkbox/util/tray/linux/GtkSystemTray.java

@@ -8,6 +8,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.CountDownLatch;
 
 import javax.swing.JMenuItem;
 import javax.swing.SwingUtilities;
@@ -32,6 +33,7 @@ public class GtkSystemTray extends SystemTray {
     private static Gobject libgobject = Gobject.INSTANCE;
     private static Gtk libgtk = Gtk.INSTANCE;
 
+    private final CountDownLatch blockUntilStarted = new CountDownLatch(1);
     private final Map<String, JMenuItem> menuEntries = new HashMap<String, JMenuItem>(2);
 
     private volatile SystemTrayMenuPopup jmenu;
@@ -103,6 +105,9 @@ public class GtkSystemTray extends SystemTray {
             this.gtkUpdateThread = new Thread() {
                 @Override
                 public void run() {
+                    // notify our main thread to continue
+                    GtkSystemTray.this.blockUntilStarted.countDown();
+
                     try {
                         libgtk.gtk_main();
                     } catch (Throwable t) {
@@ -128,7 +133,12 @@ public class GtkSystemTray extends SystemTray {
             logger.error("Error creating tray menu", e);
         }
 
-        this.active = true;
+        // we CANNOT continue until the GTK thread has started! (ignored if SWT is used)
+        try {
+            this.blockUntilStarted.await();
+            this.active = true;
+        } catch (InterruptedException e) {
+        }
     }
 
     @Override
@@ -157,6 +167,8 @@ public class GtkSystemTray extends SystemTray {
 
         this.jmenu = null;
         this.connectionStatusItem = null;
+
+        super.removeTray();
     }
 
     @Override

src/dorkbox/util/tray/swing/SwingSystemTray.java

@@ -69,6 +69,8 @@ public class SwingSystemTray extends dorkbox.util.tray.SystemTray {
                 logger.error("Error updating tray menu", e);
             }
         }
+
+        super.removeTray();
     }
 
     @Override