How to contribute a new menu to the workbench ?

Eclipse exposed a mechansim to contribute a new menu through "org.eclipse.ui.menus" extension and locationURI.
Requried extension: org.eclipse.ui.menus
LocationURI:  menu:org.eclipse.ui.main.menu

Example:
Below example will contribute a new "Cloud" menu to the eclipse workbench, and this will contain a "Upload" menu item.

 <extension
         point="org.eclipse.ui.menus">
      <menuContribution
            allPopups="false"
            locationURI="menu:org.eclipse.ui.main.menu">
         <menu
               id="com.kk.menus.cloud"
               label="Cloud">
             <command
                  commandId="com.kk.command.upload"
                  style="push">
            </command>
          </menu>
      </menuContribution>
</extension>

Command contribution to upload action:

<extension
         point="org.eclipse.ui.commands">
  <command
            id="com.kk.command.upload"
            name="Upload">
      </command>
</extension>

Handler contribution to upload action:

  <extension
         point="org.eclipse.ui.handlers">
      <handler
            class="com.kk.menus.handlers.UploadHandler"
            commandId="com.kk.command.upload">
      </handler>
   </extension>

UI Toolkits and Multi-threaded environment

For my reference:

https://weblogs.java.net/blog/kgh/archive/2004/10/multithreaded_t.html
http://www.codeaffine.com/2014/09/15/safely-use-swt-display-asyncexec/

How to get active perspective in Eclipse

Active workbench page will have getPerspective() this will return the IPerspectiveDescriptor

IWorkbench workbench = PlatformUI.getWorkbench();
if (workbench != null) {
IWorkbenchWindow activeWorkbenchWindow = workbench.getActiveWorkbenchWindow();
if (activeWorkbenchWindow != null) {
IWorkbenchPage activePage = activeWorkbenchWindow.getActivePage();
if (activePage != null) {
IPerspectiveDescriptor perspective = activePage.getPerspective();
if (perspective != null) {
String id = perspective.getId();
//This is your active perspective
}
}
}

visibleWhen on toolbar in Eclipse

I have added visibleWhen directly under toolbar, look like platform is not respecting visibleWhen for toolbar.

This is how I defined the extension:

<extension
       point="org.eclipse.ui.menus">
    <menuContribution
          allPopups="false"
          locationURI="toolbar:org.eclipse.ui.trim.vertical2">
       <toolbar
             id="com.kk.toolbar2"
             label="Charm bar">
          <command
                commandId="com.kk.command.showhelp"
                icon="icons/help.gif"
                label="Help"
                style="push">
           </command>
<visibleWhen
                   checkEnabled="false">
                <test
                      forcePluginActivation="true"
                      property="com.kk.isKKPerspective"
                      value="true">
                </test>
        </visibleWhen>
            </toolbar>
    </menuContribution>
 </extension>


visibleWhen has no effect on toolbar
https://bugs.eclipse.org/bugs/show_bug.cgi?id=201589


Workaround for this problem is, adding visibleWhen for each command. 
By adding visibleWhen on each command, toolbar is automatically getting disappeared if there are no visible elements

In my case, I want to add add a righside trim toolbar with some tool items. But I wanted to show this only in my perspective 'KKPerspective'.

<extension
       point="org.eclipse.ui.menus">
    <menuContribution
          allPopups="false"
          locationURI="toolbar:org.eclipse.ui.trim.vertical2">
       <toolbar
             id="com.kk.toolbar2"
             label="Charm bar">
          <command
                commandId="com.kk.command.showhelp"
                icon="icons/help.gif"
                label="Help"
                style="push">
             <visibleWhen
                   checkEnabled="false">
                <test
                      forcePluginActivation="true"
                      property="com.kk.isKKPerspective"
                      value="true">
                </test>
             </visibleWhen>
          </command>
            </toolbar>
    </menuContribution>
 </extension>

   <extension
         point="org.eclipse.core.expressions.propertyTesters">
      <propertyTester
            class="com.kk.KKPerspectiveTester"
            id="com.kk.propertyTester2"
            namespace="com.kk.propertyTester2"
            properties="isKKPerspective"
            type="java.lang.Object">
      </propertyTester>
   </extension>

Conventions for naming git branches for your development

Some practices which I follow for naming git branches.

If you are working on sprint/agile development, you might have planned certain activities for each sprint.

let's say, every sprint development is for 1 month,so for every sprint we can maintain different branches as mentioned below.

Example: In Development mode
Sprint 1  =>  Branch name: dev-1.0.1

here, dev-<Major version>.<Minor version>.<Sprint version>

While handing over your work to QA team, we can promote this branch to QA branch.

Example: In QA mode
dev-1.0.1 will become qa-1.0.1

If you are providing builds one top of dev branches.
Example: For sprint 1 on dev branch
com.kk.product_dev-1.0.1.0.jar

Here, <pluginname>_<<branch name>.<build number>>.jar

on QA builds generation,
com.kk.product_qa-1.0.1.0.jar

If many people are working on sprint on various features, then we can create a different branch for each feature(ex: dev-1.0.1_explorer), once the feature is stabilized then we can merge this with the main sprint branch i.e dev-1.0.1

Eclipse Plugin name and package name conventions

I will follow below conventions for naming any new plug-in which I am contributing.

Plug-in names should follow the standard Eclipse Naming conventions. That means that,
(i)   The project name on disk(Plug-in name) is the same as the plug-in id and
(ii)  Plug-in packages should start with plug-in name.
(iii) Don’t mix generated code plug-in and implementation plugins

com.kk.studio.<component name>
com.kk.studio.<major component name>.<minor component name>

 Examples:
com.kk.studio.sky   => Implemented code plug-in
com.kk.studio.sky.model    => EMF model based generated code plug-in

Package Names:
com.kk.studio.sky  => Plug-in name/Plug-in id

com.kk.studio.sky
com.kk.studio.sky.explorer
com.kk.studio.sky.explorer.model
com.kk.studio.sky.explorer.view
com.kk.studio.sky.explorer.view.actions
com.kk.studio.sky.explorer.view.dialogs
com.kk.studio.sky.explorer.view.dialogs.data
com.kk.studio.sky.explorer.view.providers
com.kk.studio.sky.i18n
com.kk.studio.sky.util


Eclipse Resources:
http://wiki.eclipse.org/Development_Resources/HOWTO/Project_Naming_Policy
http://wiki.eclipse.org/index.php/Naming_Conventions#Eclipse_Workspace_Projects

java.lang.OutOfMemoryError: unable to create new native thread

One of the developer reported "java.lang.OutOfMemoryError: unable to create new native thread" while working with eclipse on his application.

Below is the error log.

java.lang.OutOfMemoryError: unable to create new native thread

                at java.lang.Thread.start0(Native Method)

                at java.lang.Thread.start(Unknown Source)

                at java.lang.ref.Finalizer$1.run(Unknown Source)

                at java.security.AccessController.doPrivileged(Native Method)

                at java.lang.ref.Finalizer.forkSecondaryFinalizer(Unknown Source)

                at java.lang.ref.Finalizer.runFinalization(Unknown Source)

                at java.lang.Runtime.runFinalization0(Native Method)

                at java.lang.Runtime.runFinalization(Unknown Source)

                at java.lang.System.runFinalization(Unknown Source)

                at org.eclipse.ui.internal.ide.application.IDEIdleHelper$3.run(IDEIdleHelper.java:182)

                at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)

This is what i can think why he encountered with this issue.

User is running on 32 bit machine with 

Since he is running on 32 bit machine, you need to allocate –Xmx and -XX:PermSize carefully. Since 32 bit machines can address maximum of 4GB address space.

Since we allocated -Xmx is 1024m and -XX:PermSize is 512m, there is very less space is remaining to create a new Java native threads by OS.

To make it work, reduce -XX:PermSize to 256m and –Xmx to 512m(unless 1024 is required).

Expanding a trim view Vertically in programmatic way in Eclipse e4

Generally, If you have minimized a view, It will go and add it to the trimbar as shown on the left hand side.

If you click on tool item from the trimbar, it will show as a fast view. Means, It won't expand completely either in horizontally or vertically. But, user can do this by changing the orientation as show on the image.












To achieve this programmatically, we have to use Eclipse e4 workbench presentation engine component

For Vertically:
IPresentationEngine.ORIENTATION_VERTICAL

For Horizontal:
IPresentationEngine.ORIENTATION_HORIZONTAL


WorkbenchPartReference myView = page.findViewReference("myviewid");
MUIElement element = ((WorkbenchPage) page).getActiveElement(myView);

WorkbenchWindow activeWorkbenchWindow = (WorkbenchWindow) PlatformUI.getWorkbench().getActiveWorkbenchWindow();
if (activeWorkbenchWindow != null) {
MWindow window = activeWorkbenchWindow.getModel();
if (window != null) {
EModelService modelService = window.getContext().get(EModelService.class);
if (modelService != null) {
element.getTags().add(IPresentationEngine.ORIENTATION_VERTICAL);
}
}
}



By adding a element tag sets the behaviour for a particular element.

From Eclipse, "This tag can be applied to an element as a hint to the renderers that the element would prefer to be vertical. For an MPart this could be used both as a hint to how to show the view when it's in the trim but could also be used when picking a stack to add a newly opening part to. It could also be used for example to control where the tabs appear on an MPartStack."

How to minimize a view programmatically in Eclipse e4 versions/ Adding a view to the trimbar

Below snippet can be used to minimize a view.

IViewPart part = page.showView("com.kk.views.showtasks");
if (part != null) {
 IWorkbenchPartReference myView = page.findViewReference(viewid);
MUIElement element = ((WorkbenchPage) page).getActiveElement(myView);
WorkbenchWindow activeWorkbenchWindow = (WorkbenchWindow) PlatformUI.getWorkbench().getActiveWorkbenchWindow();
if (activeWorkbenchWindow != null) {
MWindow window = activeWorkbenchWindow.getModel();
if (window != null) {
            EModelService service = window.getContext().get(EModelService.class);
if (service != null) {
element.getTags().add(IPresentationEngine.MINIMIZED);

}
}
}
}

More important thing here is,
element.getTags().add(IPresentationEngine.MINIMIZED);

When above code gets invoked, MinMaxAddon.minimize(..) will be invoked internally to minimize a view. Minimized view will be added as a toolbar item to the trimbar.

MUIElement element = ((WorkbenchPage) page).getActiveElement(myView);
Here element is PartStack element, that means all the elements(Parts) which are there in the partstack will be minimized.

How to add right trimbar/side bar in eclipse

This can be achieved through "org.eclipse.ui.menus" extension point with the locationURI as "toolbar:org.eclipse.ui.trim.vertical2"

<extension
       point="org.eclipse.ui.menus">
    <menuContribution
          allPopups="false"
          locationURI="toolbar:org.eclipse.ui.trim.vertical2">
       <toolbar
             id="myrightsidetrimbar"
             label="Eclispe rightside trimbar">
          <command
                commandId="com.kk.command.showHelp"
                icon="icons/help.gif"
                label="Help"
                style="push">
          </command>
            </toolbar>
    </menuContribution>
 </extension>


toolbar:org.eclipse.ui.trim.vertical2 -> will be for used for Right trimbar

We can find all these uri identifiers in MenuUtil.java in eclipse org.eclispe.ui.workbench plugin

 /** Top Left Trim Area */
public final static String TRIM_COMMAND1 = "toolbar:org.eclipse.ui.trim.command1"; //$NON-NLS-1$
/** Top Right Trim Area */
public final static String TRIM_COMMAND2 = "toolbar:org.eclipse.ui.trim.command2"; //$NON-NLS-1$
/** Left Vertical Trim Area */
public final static String TRIM_VERTICAL1 = "toolbar:org.eclipse.ui.trim.vertical1"; //$NON-NLS-1$
/** Right Vertical Trim Area */
public final static String TRIM_VERTICAL2 = "toolbar:org.eclipse.ui.trim.vertical2"; //$NON-NLS-1$
/** Bottom (Status) Trim Area */
public final static String TRIM_STATUS = "toolbar:org.eclipse.ui.trim.status"; //$NON-NLS-1$

How to get Eclipse EModelService from workbench ?

WorkbenchWindow activeWorkbenchWindow = (WorkbenchWindow) PlatformUI.getWorkbench().getActiveWorkbenchWindow();
if (activeWorkbenchWindow != null) {
MWindow window = activeWorkbenchWindow.getModel();
if (window != null) {
EModelService modelService = window.getContext().get(EModelService.class);

//your calls
}
}

eclipse -clean option in mac os x

1. Go to eclipse directory
2. Find Eclipse Application
3. Right click on  Eclipse Application
4. It will show "Show Package Contents" menu option
4. Click on Show Package Contents
5. Go to Contents folder
6. Go to MacOS folder
7. Open the terminal
8. Drag the MacOS directory to terminal for change directory(ex: cd <macos directory>)
8. execute this " ./eclipse -clean"

eclipse.ini file in Mac os x

1. Go to eclipse directory
2. Find Eclipse Application
3. Right click on  Eclipse Application
4. It will show "Show Package Contents" menu option
4. Click on Show Package Contents
5. Go to Contents
6. Go to MacOS
7. Look for eclipse.ini file

Unsupported major.minor version 51.0

java.lang.UnsupportedClassVersionError happens because of a higher JDK during compile time and lower JDK during runtime.

51.0 in "Unsupported major.minor version 51.0" represents that, .class file generated with JDK 1.7 and but you are trying with run with(runtime) with lower version of it.

Below are the version numbers and compatible JDK's.

J2SE 8 = 52,
J2SE 7 = 51,
J2SE 6.0 = 50,
J2SE 5.0 = 49,
JDK 1.4 = 48,
JDK 1.3 = 47,
JDK 1.2 = 46,
JDK 1.1 = 45


To resolve this issue, make use of same version during the compile time and run-time.

Example: You would have generatd jar file with jdk 1.7 and but you are trying to run that jar using JDK 1.6 eclipse, this leads to above error.