some.process MANIFEST.MF:

Manifest-Version: 1.0
Bundle-ManifestVersion: 2
Bundle-Name: Process Plug-in
Bundle-SymbolicName: some.process
Bundle-Version: 1.0.0
Bundle-Activator: some.process.Activator
Require-Bundle: org.eclipse.core.runtime
Eclipse-LazyStart: true
Bundle-RequiredExecutionEnvironment: JavaSE-1.6

some.process.Activator:
package some.process;

import org.eclipse.core.runtime.Plugin;
import org.osgi.framework.BundleContext;

/**
 * The activator class controls the plug-in life cycle
 */
public class Activator extends Plugin {

	// The plug-in ID
	public static final String PLUGIN_ID = "some.process";

	// The shared instance
	private static Activator plugin;
	
	/**
	 * The constructor
	 */
	public Activator() {
	}

	/*
	 * (non-Javadoc)
	 * @see org.eclipse.core.runtime.Plugins#start(org.osgi.framework.BundleContext)
	 */
	public void start(BundleContext context) throws Exception {
		super.start(context);
		System.err.println("I'm running");
		Runtime.getRuntime().exec("runserver");
		plugin = this;
	}

	/*
	 * (non-Javadoc)
	 * @see org.eclipse.core.runtime.Plugin#stop(org.osgi.framework.BundleContext)
	 */
	public void stop(BundleContext context) throws Exception {
		plugin = null;
		super.stop(context);
	}

	/**
	 * Returns the shared instance
	 *
	 * @return the shared instance
	 */
	public static Activator getDefault() {
		return plugin;
	}

}