单例模式

package cn;

/**
 * 测试单例模式
 * @author xiaoming
 *
 */
public class TaskManager {

  private static TaskManager tm = null;

	
	//因此需要将TaskManager的构造函数可见性改为private	
	private TaskManager() {

	}
	
	public void displayProcesses() {
	}
	
	public void displayServices() {
	}
	
	public static TaskManager getInstance() {
		if (tm == null) {
			tm = new TaskManager();
		} 
		return tm;
	}
}