Copying files from Windows to Mac OS

For my reference

Download this software in Windows, this will allow to get the access to Mac os and you can easily transfer files from windows to mac using this.

http://winscp.net/eng/download.php

Maximum heap size allocated on 32 bit JVM's

http://www.oracle.com/technetwork/java/hotspotfaq-138619.html#gc_heap_32bit

The maximum theoretical heap limit for the 32-bit JVM is 4G. Due to various additional constraints such as available swap, kernel address space usage, memory fragmentation, and VM overhead, in practice the limit can be much lower. On most modern 32-bit Windows systems the maximum heap size will range from 1.4G to 1.6G. On 32-bit Solaris kernels the address space is limited to 2G. On 64-bit operating systems running the 32-bit VM, the max heap size can be higher, approaching 4G on many Solaris systems.

In nutshell:
Theoretically : 4GB
Practically:  1.4 to 1.6GB

Where can I find eclipse preferences stored files ?

Eclipse stores all the preferences in the preference configuration files. This you can find in the below eclipse workspace location.

<eclipseworkspace>\.metadata\.plugins\org.eclipse.core.runtime\.settings\

Say for example, jre configuration will be stored in the "org.eclipse.jdt.launching.prefs" file.

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>