The Hello World manifests

Before we run the new view, let's take a look at the manifest files that were generated for us. First, double-click the plugin.xml file to open the plug-in editor and select the plugin.xml tab.

<?xml version="1.0" encoding="UTF-8"?>
<?eclipse version="3.2"?>
<plugin>
	<extension point="org.eclipse.ui.views">
		<category
			name="Hello Category"
			id="com.example.helloworld">
		</category>
		<view
			name="Hello View"
			icon="icons/sample.gif"
			category="com.example.helloworld"
			class="com.example.helloworld.views.HelloWorldView"
			id="com.example.helloworld.views.HelloWorldView">
		</view>
	</extension>
</plugin>

The information about the view that we provided when we created the plug-in project was used to generate an entry in the plugin.xml file that defines our view extension. In the extension definition, we define a category for the view, including its name and id. We then define the view itself, including its name and id, and we associate it with the category using the id we defined for our category. We also specify the class that implements our view, HelloWorldView.

As you can see, the plug-in manifest file wraps up all the information about our extension and how to run it into a nice, neat package.

The other manifest file that is generated by the PDE is the OSGi manifest, MANIFEST.MF. This file is created in the META-INF directory of the plug-in project, but is most easily viewed by clicking on the MANIFEST.MF tab of the plug-in editor. The OSGi manifest describes lower-level information about the packaging of the plug-in, using the OSGi bundle terminology. It contains information such as the name of the plug-in (bundle) and the bundles that it requires.