if (!xmlFileIsValid){
//show alert "please set a valid xml file in the eclipse preferences"
return;
}

<plugin>
   <extension
         point="org.eclipse.ui.views">
      <category
            name="My Category"
            id="my-plugin">
      </category>
      <view
            name="My View"
            icon="icons/sample.gif"
            category="my-plugin"
            class="my.plugin.package.views.MyView"
            id="my.plugin.views.MyView">
      </view>
   </extension>
   <extension
         point="org.eclipse.ui.perspectiveExtensions">
      <perspectiveExtension
            targetID="org.eclipse.jdt.ui.JavaPerspective">
         <view
               ratio="0.5"
               relative="org.eclipse.ui.views.TaskList"
               relationship="right"
               id="my.plugin.views.MyView">
         </view>
      </perspectiveExtension>
   </extension>
   <extension
         point="org.eclipse.ui.popupMenus">
   <objectContribution
            adaptable="false"
            id="my-plugin.PluginManagerObjectContribution"
            nameFilter="*.*"
            objectClass="org.eclipse.ui.IEditorInput">
           <menu
                icon="icons/sample.gif"
                id="my-plugin-pluginManager.popupSubMenu"
                label="My View"
                path="additions">
             <groupMarker
                   name="content">
             </groupMarker>
          </menu>
         <action
               class="my.plugin.package.actions.AnAction"
               enablesFor="1"
               icon="icons/sample.gif"
               id="my-plugin.action1"
               label="Do something with the selected text"
               menubarPath="my-plugin-pluginManager.popupSubMenu/content"
               tooltip="Do something with the selected text">
         </action>
         <action
               class="my.plugin.package.actions.AnotherAction"
               enablesFor="1"
               icon="icons/sample.gif"
               id="my-plugin.action2"
               menubarPath="my-plugin-pluginManager.popupSubMenu/content"
               label="Do something else with the selected text"
               tooltip="Do something else with the selected text">
         </action>
         
      </objectContribution>
   </extension>
   <extension
         point="org.eclipse.ui.preferencePages">
      <page
            class="my.plugin.package.preferences.MyViewPreferencePage"
            id="my.plugin.package.preferences.MyViewPreferencePage"
            name="My View Preferences">
      </page>
   </extension>
   <extension
         point="org.eclipse.core.runtime.preferences">
      <initializer
            class="my.plugin.package.preferences.PreferenceInitializer">
      </initializer>
   </extension>
 
</plugin>