Plugin Development: Eclipse hangs when testing plugin - eclipse-plugin

Question

I am new to developing plugins, and was wondering what causes a test plugin to hang when started i.e. Eclipse is unresponsive.
I know that my code is working as I developed a voice recognition plugin to write to the screen what is said and when I open notepad everything I say is printed to notepad.
So I was wondering, am I missing something in the plugin life-cycle that causes the IDE to hang when my plugin is started?
package recognise.handlers;
public class SampleHandler extends AbstractHandler {
public SampleHandler() {
}
/**
* the command has been executed, so extract extract the needed information
* from the application context.
*/
public Object execute(ExecutionEvent event) throws ExecutionException {
boolean finish = false;
IWorkbenchWindow window = HandlerUtil.getActiveWorkbenchWindowChecked(event);
MessageDialog.openInformation(
window.getShell(),
"Recognise",
"Starting Recognition");
TakeInput start = new TakeInput();
//Stage a = new Stage();
//SceneManager scene = new SceneManager();
try {
start.startVoiceRecognition(finish);
//scene.start(a);
} catch (IOException | AWTException e) {
e.printStackTrace();
}
return null;
}
}
Does the start.startVoiceRecognition() need to be threaded?
Thanks in advance and let me know if you would like to see my manifest/activator etc.
Conclusion
Added a job separate to the UI thread
/*
* Start a new job separate to the main thread so the UI will not
* become unresponsive when the plugin has started
*/
public void runVoiceRecognitionJob() {
Job job = new Job("Voice Recognition Job") {
#Override
protected IStatus run(IProgressMonitor monitor) {
TakeInput start = new TakeInput();
try {
start.startVoiceRecognition(true);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (AWTException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// use this to open a Shell in the UI thread
return Status.OK_STATUS;
}
};
job.setUser(true);
job.schedule();
}

Answer 1

As shown start.startVoiceRecognition() is running in the UI thread, and it will block the UI thread until it is finished and the app will be unresponsive during that time. So if it is doing a significant amount of work either use a Thread or use an Eclipse Job (which runs work in a background thread managed by Eclipse).

Answer 2

To unblock your UI you have to use Display thread.
/**
* the command has been executed, so extract extract the needed information
* from the application context.
*/
public Object execute(ExecutionEvent event) throws ExecutionException {
Display.getDefault().asyncExec(new Runnable() {
public void run() {
boolean finish = false;
IWorkbenchWindow window = HandlerUtil.getActiveWorkbenchWindowChecked(event);
MessageDialog.openInformation(
window.getShell(),
"Recognise",
"Starting Recognition");
TakeInput start = new TakeInput();
//Stage a = new Stage();
//SceneManager scene = new SceneManager();
try {
start.startVoiceRecognition(finish);
//scene.start(a);
} catch (IOException | AWTException e) {
e.printStackTrace();
}
MessageDialog.openInformation(shell, "Your Popup ",
"Your job has finished.");
}
});
return null;
}
You can use Display.getDefault().asyncExec() as mentioned above, so your UI will be unblocked, while your non UI code will be executing.