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Need Eclipse IDE Plugin Dev Help: Rename File Resource of the Active Editor, TextEditor

From a plug-in in Eclipse, I have bound a key combination to attempt to use the Project Explorer refactor dialog to rename a file resource that is being edited by a TextEditor. The editor is the active selected view at the time. I am so far unsuccessful.
If I bind another key combination to the same command ID, that is "org.eclipse.ui.edit.rename", Then manually select the file resource in the Project Explorer and do the key sequence, the dialog does indeed present itself. Does this imply that I need to programatically give the Project Explorer focus?
Can anyone offer suggestions how I can programatically refactor/rename the resource associated with the active editor? I don't want to do "Save As" as this commits the change to disk and I don't want to force the user to do that yet.
The following is my test code called by the handler for the custom key binding command.
public Object execute( ExecutionEvent event ) throws ExecutionException
{
IWorkbenchWindow window = HandlerUtil.getActiveWorkbenchWindowChecked( event );
if( window == null ) return null;
IWorkbenchPage workbench_page = window.getActivePage();
if( workbench_page == null ) return null;
IEditorPart active_editor = workbench_page.getActiveEditor();
if( !( active_editor instanceof ITextEditor ) ) return null;
// Not used here yet...
StyledText styled_text = (StyledText)( (ITextEditor)active_editor).getAdapter( Control.class );
Display display = styled_text.getDisplay();
switch( event.getCommand().getId() )
{
case "test.commands.sampleCommand":
{
IViewPart view_part = workbench_page.findView( "org.eclipse.ui.navigator.ProjectExplorer" );
if( ( view_part != null ) && ( view_part instanceof ProjectExplorer ) )
{
// Try and select the resource. This does not seem to do anything visually...
IPath path = ( (IPathEditorInput)active_editor.getEditorInput() ).getPath();
if( path == null ) return null;
( (ISetSelectionTarget)view_part ).selectReveal( new StructuredSelection( path ) );
ICommandService command_service = ( (ProjectExplorer)view_part ).getViewSite().getService( ICommandService.class );
if( command_service == null ) return null;
Command file_rename_command = command_service.getCommand( IWorkbenchCommandConstants.FILE_RENAME );
try
{
// Rename the selected resource.
file_rename_command.executeWithChecks( new ExecutionEvent() );
}
catch( NotDefinedException | NotEnabledException | NotHandledException exception )
{
log_error( "Did not work :", exception );
return null;
}
log_info( "Success :" + view_part.toString() );
}
return null;
}
default: return null;
}
}
The following is the resultant debug log output.
!ENTRY test 1 0 2019-12-19 09:47:06.902
!MESSAGE Did not work :
!STACK 0
org.eclipse.core.commands.NotHandledException: There is no handler to execute for command org.eclipse.ui.edit.rename
at org.eclipse.core.commands.Command.executeWithChecks(Command.java:511)
at test.Activator.execute(Activator.java:125)
at test.handlers.SampleHandler.execute(SampleHandler.java:18)
at org.eclipse.ui.internal.handlers.HandlerProxy.execute(HandlerProxy.java:283)
at org.eclipse.ui.internal.handlers.E4HandlerProxy.execute(E4HandlerProxy.java:95)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:58)
at org.eclipse.e4.core.internal.di.InjectorImpl.invokeUsingClass(InjectorImpl.java:318)
at org.eclipse.e4.core.internal.di.InjectorImpl.invoke(InjectorImpl.java:252)
at org.eclipse.e4.core.contexts.ContextInjectionFactory.invoke(ContextInjectionFactory.java:173)
at org.eclipse.e4.core.commands.internal.HandlerServiceHandler.execute(HandlerServiceHandler.java:156)
at org.eclipse.core.commands.Command.executeWithChecks(Command.java:498)
at org.eclipse.core.commands.ParameterizedCommand.executeWithChecks(ParameterizedCommand.java:487)
at org.eclipse.e4.core.commands.internal.HandlerServiceImpl.executeHandler(HandlerServiceImpl.java:213)
at org.eclipse.e4.ui.bindings.keys.KeyBindingDispatcher.executeCommand(KeyBindingDispatcher.java:308)
at org.eclipse.e4.ui.bindings.keys.KeyBindingDispatcher.press(KeyBindingDispatcher.java:584)
at org.eclipse.e4.ui.bindings.keys.KeyBindingDispatcher.processKeyEvent(KeyBindingDispatcher.java:653)
at org.eclipse.e4.ui.bindings.keys.KeyBindingDispatcher.filterKeySequenceBindings(KeyBindingDispatcher.java:443)
at org.eclipse.e4.ui.bindings.keys.KeyBindingDispatcher.access$2(KeyBindingDispatcher.java:386)
at org.eclipse.e4.ui.bindings.keys.KeyBindingDispatcher$KeyDownFilter.handleEvent(KeyBindingDispatcher.java:96)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:89)
at org.eclipse.swt.widgets.Display.filterEvent(Display.java:1199)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1056)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1081)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1066)
at org.eclipse.swt.widgets.Widget.sendKeyEvent(Widget.java:1108)
at org.eclipse.swt.widgets.Widget.sendKeyEvent(Widget.java:1104)
at org.eclipse.swt.widgets.Widget.wmKeyDown(Widget.java:1759)
at org.eclipse.swt.widgets.Control.WM_KEYDOWN(Control.java:5146)
at org.eclipse.swt.widgets.Canvas.WM_KEYDOWN(Canvas.java:414)
at org.eclipse.swt.widgets.Control.windowProc(Control.java:4793)
at org.eclipse.swt.widgets.Canvas.windowProc(Canvas.java:348)
at org.eclipse.swt.widgets.Display.windowProc(Display.java:4820)
at org.eclipse.swt.internal.win32.OS.DispatchMessage(Native Method)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3583)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1160)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1049)
at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:155)
at org.eclipse.ui.internal.Workbench.lambda$3(Workbench.java:633)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:557)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:150)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:150)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:203)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:137)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:107)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:400)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:255)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:660)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:597)
at org.eclipse.equinox.launcher.Main.run(Main.java:1468)
at org.eclipse.equinox.launcher.Main.main(Main.java:1441)
Thanks and BR,
Ralph
PS,
Full discosure, I asked this question in the eclipse forums also.

JavaFx ListView<Float> set all items font color

I have a problem in updating an item in a listview, I' m trying to change the font color in a listview by the number.
I mean if the number is < 6.0, the specific item font color should be red, otherwise it should be green.
Here's the code I tried:
public void loadMarksListView(String key){
ObservableList<Float> items = FXCollections.observableArrayList();
items.addAll(subjectsMarks.get(key));
marksListView.setItems(items);
marksListView.setCellFactory(new Callback<ListView<Float>, ListCell<Float>>() {
#Override
public ListCell<Float> call(ListView<Float> param) {
return new ColoredCell();
}
});
}
static class ColoredCell extends ListCell<Float>{
#Override
public void updateItem(Float number, boolean empty) {
super.updateItem(number, empty);
if (Float.parseFloat(number.getClass().toString()) < 6.0f){
this.setTextFill(Color.RED);
}
else{
this.setTextFill(Color.GREEN);
}
}
}
EDIT
Stack trace
Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
at main.Controller$ColoredCell.updateItem(Controller.java:88)
at main.Controller$ColoredCell.updateItem(Controller.java:83)
at javafx.scene.control.ListCell.updateItem(ListCell.java:480)
at javafx.scene.control.ListCell.access$300(ListCell.java:72)
at javafx.scene.control.ListCell$4.invalidated(ListCell.java:299)
at javafx.beans.property.ObjectPropertyBase.markInvalid(ObjectPropertyBase.java:111)
at javafx.beans.property.ObjectPropertyBase.set(ObjectPropertyBase.java:146)
at javafx.scene.control.ListCell.setListView(ListCell.java:305)
at javafx.scene.control.ListCell.updateListView(ListCell.java:494)
at com.sun.javafx.scene.control.skin.ListViewSkin.createCell(ListViewSkin.java:292)
at com.sun.javafx.scene.control.skin.ListViewSkin.lambda$new$366(ListViewSkin.java:99)
at com.sun.javafx.scene.control.skin.VirtualFlow.getCell(VirtualFlow.java:1777)
at com.sun.javafx.scene.control.skin.VirtualFlow.getCellLength(VirtualFlow.java:1879)
at com.sun.javafx.scene.control.skin.VirtualFlow.computeViewportOffset(VirtualFlow.java:2528)
at com.sun.javafx.scene.control.skin.VirtualFlow.layoutChildren(VirtualFlow.java:1189)
at javafx.scene.Parent.layout(Parent.java:1087)
at javafx.scene.Parent.layout(Parent.java:1093)
at javafx.scene.Parent.layout(Parent.java:1093)
at javafx.scene.Parent.layout(Parent.java:1093)
at javafx.scene.Scene.doLayoutPass(Scene.java:552)
at javafx.scene.Scene$ScenePulseListener.pulse(Scene.java:2397)
at com.sun.javafx.tk.Toolkit.lambda$runPulse$30(Toolkit.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.Toolkit.runPulse(Toolkit.java:354)
at com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:381)
at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:510)
at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:490)
at com.sun.javafx.tk.quantum.QuantumToolkit.lambda$runToolkit$404(QuantumToolkit.java:319)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
at com.sun.glass.ui.gtk.GtkApplication.lambda$null$49(GtkApplication.java:139)
at java.lang.Thread.run(Thread.java:745)
Process finished with exit code 0

The problem is that in your updateItem() method you have to check if the item is empty like this:
static class ColoredCell extends ListCell<Float>{
#Override
public void updateItem(Float number, boolean empty) {
super.updateItem(number, empty);
if(number == null || empty) {
setText(null);
setGraphic(null);
} else {
setText(number.toString()); // This line is very important!
if (number < 6.0f){
this.setTextFill(Color.RED);
} else {
this.setTextFill(Color.GREEN);
}
}
}
}
EDIT:
You have to set the text of the cell manually because you are redefining how the cell will be rendered so you have to add all the graphical components and values needed (for exemple if you want to add an icon for each mark, due to the fact that you don't use the default cell anymore, you have to call in the ColoredCell class the setGraphic() method.

Why is my JSONObject related unit test failing?

I'm running my tests using gradle testFlavorType
JSONObject jsonObject1 = new JSONObject();
JSONObject jsonObject2 = new JSONObject();
jsonObject1.put("test", "test");
jsonObject2.put("test", "test");
assertEquals(jsonObject1.get("test"), jsonObject2.get("test"));
The above test succeeds.
jsonObject = new SlackMessageRequest(channel, message).buildBody();
String channelAssertion = jsonObject.getString(SlackMessageRequest.JSON_KEY_CHANNEL);
String messageAssertion = jsonObject.getString(SlackMessageRequest.JSON_KEY_TEXT);
assertEquals(channel, channelAssertion);
assertEquals(message, messageAssertion);
But the above two requests fail. The stack trace says that channelAssertion and messageAssertion are null, but not sure why. My question is: Why are the above two asserts failing?
Below is the SlackMessageRequest.
public class SlackMessageRequest
extends BaseRequest {
// region Variables
public static final String JSON_KEY_TEXT = "text";
public static final String JSON_KEY_CHANNEL = "channel";
private String mChannel;
private String mMessage;
// endregion
// region Constructors
public SlackMessageRequest(String channel, String message) {
mChannel = channel;
mMessage = message;
}
// endregion
// region Methods
#Override
public MethodType getMethodType() {
return MethodType.POST;
}
#Override
public JSONObject buildBody() throws JSONException {
JSONObject body = new JSONObject();
body.put(JSON_KEY_TEXT, getMessage());
body.put(JSON_KEY_CHANNEL, getChannel());
return body;
}
#Override
public String getUrl() {
return "http://localhost:1337";
}
public String getMessage() {
return mMessage;
}
public String getChannel() {
return mChannel;
}
// endregion
}
Below is the stacktrace:
junit.framework.ComparisonFailure: expected:<#tk> but was:<null>
at junit.framework.Assert.assertEquals(Assert.java:100)
at junit.framework.Assert.assertEquals(Assert.java:107)
at junit.framework.TestCase.assertEquals(TestCase.java:269)
at com.example.app.http.request.SlackMessageRequestTest.testBuildBody(SlackMessageRequestTest.java:30)
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:483)
at junit.framework.TestCase.runTest(TestCase.java:176)
at junit.framework.TestCase.runBare(TestCase.java:141)
at junit.framework.TestResult$1.protect(TestResult.java:122)
at junit.framework.TestResult.runProtected(TestResult.java:142)
at junit.framework.TestResult.run(TestResult.java:125)
at junit.framework.TestCase.run(TestCase.java:129)
at junit.framework.TestSuite.runTest(TestSuite.java:252)
at junit.framework.TestSuite.run(TestSuite.java:247)
at org.junit.internal.runners.JUnit38ClassRunner.run(JUnit38ClassRunner.java:86)
at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecuter.runTestClass(JUnitTestClassExecuter.java:86)
at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecuter.execute(JUnitTestClassExecuter.java:49)
at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassProcessor.processTestClass(JUnitTestClassProcessor.java:64)
at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:50)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)
at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
at org.gradle.messaging.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:32)
at org.gradle.messaging.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:93)
at com.sun.proxy.$Proxy2.processTestClass(Unknown Source)
at org.gradle.api.internal.tasks.testing.worker.TestWorker.processTestClass(TestWorker.java:106)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)
at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
at org.gradle.messaging.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:360)
at org.gradle.internal.concurrent.DefaultExecutorFactory$StoppableExecutorImpl$1.run(DefaultExecutorFactory.java:64)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
EDIT 5:55PM EST
I've figured out that I can log with System.out.println("") and then see the results by running gradle testFlavorType --debug and by trial and error I've discovered the following weird situation:
#Override
public JSONObject buildBody() throws JSONException {
System.out.println("buildBody mChannel = " + mChannel);
System.out.println("buildBody mMessage = " + mMessage);
JSONObject body = new JSONObject();
body.put(JSON_KEY_TEXT, getMessage());
body.put(JSON_KEY_CHANNEL, getChannel());
if (body.length() != 0) {
Iterator<String> keys = body.keys();
if (keys.hasNext()) {
do {
String key = keys.next();
System.out.println("keys: " + key);
} while (keys.hasNext());
}
} else {
System.out.println("There are no keys????");
}
return body;
}
For some reason, "There are no keys????" is printing out?!?!?!?! Why?!
EDIT 6:20PM EST
I've figured out how to debug unit tests. According to the debugger, the assigned JSONObject is returning "null". I have no clue what this means (see below). Since I think this is relevant, my gradle file includes the following:
testOptions {
unitTests.returnDefaultValues = true
}
It's especially strange because if I construct a JSONObject inside the test, then everything works fine. But if it is part of the original application's code, then it doesn't work and does the above.

As Lucas says, JSON is bundled up with the Android SDK, so you are working with a stub.
The current solution is to pull JSON from Maven Central like this:
dependencies {
...
testImplementation 'org.json:json:20210307'
}
You can replace the version 20210307 with the the latest one depending on the Android API. It is not known which version of the maven artefact corresponds exactly/most closely to what ships with Android.
Alternatively, you can download and include the jar:
dependencies {
...
testImplementation files('libs/json.jar')
}
Note that you also need to use Android Studio 1.1 or higher and at least build tools version 22.0.0 or above for this to work.
Related issue: #179461

The class JSONObject is part of the android SDK. That means that is not available for unit testing by default.
From http://tools.android.com/tech-docs/unit-testing-support
The android.jar file that is used to run unit tests does not contain
any actual code - that is provided by the Android system image on real
devices. Instead, all methods throw exceptions (by default). This is
to make sure your unit tests only test your code and do not depend on
any particular behaviour of the Android platform (that you have not
explicitly mocked e.g. using Mockito).
When you set the test options to
testOptions {
unitTests.returnDefaultValues = true
}
you are fixing the "Method ... not mocked." problem, but the outcome is that when your code uses new JSONObject() you are not using the real method, you are using a mock method that doesn't do anything, it just returns a default value. That's the reason the object is null.
You can find different ways of solving the problem in this question: Android methods are not mocked when using Mockito

Well, my first hunch would be that your getMessage() method returns null. You could show the body of that method in your question and have us find the answer for you, but you should probably research how to debug android applications using breakpoints.
That way you can run your code step by step and see the values of each variable at every step. That would show you your problem in no time, and it's a skill you should definitely master as soon as possible if you intend to get seriously involved in programming.

Perspective not loading in RCP when tried more than one

I am creating a RCP application. I have a view class NewView.
public class NewView extends ViewPart {
private DataBindingContext m_bindingContext;
public static final String ID = "com.app.Editor.newView";
SaveNewFileBean bean = new SaveNewFileBean();
private StyledText text;
public NewView() {
}
#Override
public void createPartControl(Composite parent) {
text = new StyledText(parent, SWT.BORDER);
m_bindingContext = initDataBindings();
}
public String returnText(){
String textData = bean.getText();
return textData;
}
#Override
public void setFocus() {
}
protected DataBindingContext initDataBindings() {
DataBindingContext bindingContext = new DataBindingContext();
//
IObservableValue observeTextTextObserveWidget = WidgetProperties.text(SWT.Modify).observe(text);
IObservableValue textBeanObserveValue = PojoProperties.value("text").observe(bean);
bindingContext.bindValue(observeTextTextObserveWidget, textBeanObserveValue, null, null);
//
return bindingContext;
}
}
When I am running the application first time, I click on New Menu and everything everything is working fine. But, When I am trying to load it again by clicking on New again, it doesn't give any error. But, it doesn't load the perspective also.
Is there some issue with my code?
Thanks!
edit: New is command. New calls a handler NewFileHandler which in turn calls NewView.java using the below code.
public class NewFileHandler extends AbstractHandler {
#Override
public Object execute(ExecutionEvent event) throws ExecutionException {
SwitchPerspectiveAction action = new SwitchPerspectiveAction();
action.run(NewFilePerspective.ID);
return null;
}
}
SwitchPerspectiveASction Class
public class SwitchPerspectiveAction extends Action {
public void run(String newPerspectiveID) {
if (PlatformUI.getWorkbench() != null) {
try {
PlatformUI.getWorkbench().showPerspective(newPerspectiveID,
PlatformUI.getWorkbench().getActiveWorkbenchWindow());
} catch (WorkbenchException e) {
e.printStackTrace();
}
}
}
}
edit:
I tried with this code.
IWorkbenchPage page = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage();
try {
page.showView(OpenFilePerspective.ID, "1" , IWorkbenchPage.VIEW_ACTIVATE);
} catch (PartInitException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
GIves error.
org.eclipse.ui.PartInitException: Could not create view: com.app.Editor.openFileperspective:1
at org.eclipse.ui.internal.WorkbenchPage.busyShowView(WorkbenchPage.java:1275)
at org.eclipse.ui.internal.WorkbenchPage$14.run(WorkbenchPage.java:4208)
at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
at org.eclipse.ui.internal.WorkbenchPage.showView(WorkbenchPage.java:4204)
at com.app.editor.handlers.OpenHandler.execute(OpenHandler.java:66)
at org.eclipse.ui.internal.handlers.HandlerProxy.execute(HandlerProxy.java:294)
at org.eclipse.ui.internal.handlers.E4HandlerProxy.execute(E4HandlerProxy.java:90)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:55)
at org.eclipse.e4.core.internal.di.InjectorImpl.invokeUsingClass(InjectorImpl.java:247)
at org.eclipse.e4.core.internal.di.InjectorImpl.invoke(InjectorImpl.java:229)
at org.eclipse.e4.core.contexts.ContextInjectionFactory.invoke(ContextInjectionFactory.java:132)
at org.eclipse.e4.core.commands.internal.HandlerServiceHandler.execute(HandlerServiceHandler.java:149)
at org.eclipse.core.commands.Command.executeWithChecks(Command.java:499)
at org.eclipse.core.commands.ParameterizedCommand.executeWithChecks(ParameterizedCommand.java:508)
at org.eclipse.e4.core.commands.internal.HandlerServiceImpl.executeHandler(HandlerServiceImpl.java:210)
at org.eclipse.e4.ui.workbench.renderers.swt.HandledContributionItem.executeItem(HandledContributionItem.java:825)
at org.eclipse.e4.ui.workbench.renderers.swt.HandledContributionItem.handleWidgetSelection(HandledContributionItem.java:701)
at org.eclipse.e4.ui.workbench.renderers.swt.HandledContributionItem.access$6(HandledContributionItem.java:685)
at org.eclipse.e4.ui.workbench.renderers.swt.HandledContributionItem$4.handleEvent(HandledContributionItem.java:613)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4353)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1061)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4172)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3761)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$9.run(PartRenderingEngine.java:1151)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1032)
at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:148)
at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:636)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:579)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:150)
at com.app.editor.Application.start(Application.java:20)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:134)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:380)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:235)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:648)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:603)
at org.eclipse.equinox.launcher.Main.run(Main.java:1465)
at org.eclipse.equinox.launcher.Main.main(Main.java:1438)

showPerspective doesn't do anything if the perspective is already open. You can't use this to open multiple copies of the same view.
If you just want to open a view use:
IWorkbenchPage page = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage();
IViewPart viewPart = page.showView("the view id");
Note that this will only show one instance of the view at a time.
To close a view use:
page.hideView(viewPart);
You can show multiple copies of a view by using a secondary id for the view:
page.showView("view id", "secondary id", IWorkbenchPage.VIEW_ACTIVATE);
The secondary id does not have to be defined anywhere. It just needs to be unique for each view you want to show.

IndexOutOfBoundException when trying to write in response in wicket

I have a wicket page like this:
public final class Services extends WebPage {
public Services() {
super();
}
public Services(PageParameters params) {
StringValue serviceType = params.get("name");
if("report".equals(serviceType.toString())) {
this.getResponse().write("HelloWorld");
}
}
}
and it's html is empty.
when I call URL of this page I see this error
Index: 0, Size: 0
java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
at java.util.ArrayList.rangeCheck(ArrayList.java:604)
at java.util.ArrayList.get(ArrayList.java:382)
at java.util.Collections$UnmodifiableList.get(Collections.java:1211)
at org.apache.wicket.markup.Markup.get(Markup.java:130)
at org.apache.wicket.Component.internalRender(Component.java:2356)
at org.apache.wicket.Component.render(Component.java:2307)
at org.apache.wicket.Page.renderPage(Page.java:1010)
at org.apache.wicket.request.handler.render.WebPageRenderer.renderPage(WebPageRenderer.java:121)
at org.apache.wicket.request.handler.render.WebPageRenderer.respond(WebPageRenderer.java:271)
at org.apache.wicket.core.request.handler.RenderPageRequestHandler.respond(RenderPageRequestHandler.java:165)
at org.apache.wicket.request.cycle.RequestCycle$HandlerExecutor.respond(RequestCycle.java:861)
at org.apache.wicket.request.RequestHandlerStack.execute(RequestHandlerStack.java:64)
at org.apache.wicket.request.cycle.RequestCycle.execute(RequestCycle.java:261)
at org.apache.wicket.request.cycle.RequestCycle.processRequest(RequestCycle.java:218)
at org.apache.wicket.request.cycle.RequestCycle.processRequestAndDetach(RequestCycle.java:289)
at org.apache.wicket.protocol.http.WicketFilter.processRequestCycle(WicketFilter.java:259)
at org.apache.wicket.protocol.http.WicketFilter.processRequest(WicketFilter.java:201)
at org.apache.wicket.protocol.http.WicketFilter.doFilter(WicketFilter.java:282)
...
i don't know really what is wrong in my simple wicket page.

Wicket ever expects some markup in the associated HTML template to the code. The line that is the originator of your Exception is in Component.class see
private final void internalRender()
{
...
MarkupElement elem = markup.get(0);
...
}
That code gets a 'root' element of the associated markup. A code without any markup is a non-sence in Wicket.
TIP: If you just want to handle a request, mount a shareable resource or some of other resources other then a page.