首先来个一次性单线程版

public static void main(String[] args){
  new Thread(new Runnable() {
   public void run() {
    System.out.println("Do what you want to do background.");
   }   
  }
  ).start();  
  System.out.println("Do what you want to do now");
 }

另外也可以利用java的线程池来处理频繁的线程作业。

int minSize = 10;//当池子大小小于minSize就新建线程，并处理请求
int queueSize = 20;//当池子大小等于minSize，把请求放入workQueue,如果workQueue中的等待请求数达到queueSize时，新建线程入池，并处理请求
int maxSize = 20;//新建请求使池子大小撑到了maxSize就用RejectedExecutionHandler来做拒绝处理
long aliveTime = 30;//另外，当池子的线程数大于minSize的时候，多余的线程会等待aliveTime长的时间，如果无请求可处理就自行销毁		
BlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<Runnable>(queueSize);//当池子里有空闲线程时就去从workQueue中取任务并处理
RejectedExecutionHandler handler = new ThreadPoolExecutor.CallerRunsPolicy();//请求数超过maxsize+queuesize时，进行拒绝处理
ThreadPoolExecutor pool = new ThreadPoolExecutor(minSize, maxSize, aliveTime, TimeUnit.SECONDS, workQueue, handler);
pool.execute(new Runnable() {
		public void run() {
		System.out.println("Do what you want to do.");
		}			
	}
);