@Inject
IStatusLineManager statusLine;
...
statusLine.setMessage(msg);

/*******************************************************************************
 * Copyright (c) 2010 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package de.testplugin.test.handlers;

import javax.inject.Inject;
import javax.inject.Named;

import org.eclipse.e4.core.di.annotations.Execute;
import org.eclipse.e4.ui.services.IServiceConstants;
import org.eclipse.jface.action.IStatusLineManager;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.swt.widgets.Shell;

public class AboutHandler {
	@Inject
	IStatusLineManager statusLine;
	
	@Execute
	public void execute(@Named(IServiceConstants.ACTIVE_SHELL) Shell shell) {
		statusLine.setMessage("text");
		MessageDialog.openInformation(shell, "About", "e4 Application example.");
	}
}

public class StatusLine {

	public StatusLine() {
	}

	/**
	 * Create contents of the StatusLine
	 */
	
	@PostConstruct
	public void createControls(Composite parent, IStatusLineManager statusManager) {
		
		
		StatusLineContributionItem field = new StatusLineContributionItem("HelloWorld");
		field.setText("Hello World");
		statusManager.add(field);

	}

	@PreDestroy
	public void dispose() {
	}

	@Focus
	public void setFocus() {
		// TODO	Set the focus to control
	}
}