两个线程与stringbuffer和stringbuiler以及lock synchronized线程测试

 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;

 public  class RunnableTest2 {
 //    private StringBuilder sb = new StringBuilder();
     private StringBuffer sb = new StringBuffer();
     inc i1 = new inc();
     dec d1 = new dec();
     private Lock lock = new ReentrantLock();
     private boolean ok = false;
     public static void main(String[] args) throws InterruptedException {
         RunnableTest2 tr = new RunnableTest2();
         double time = System.currentTimeMillis();
         for(int i=0;i<1;i++) {
             new Thread(tr.i1).start();
             new Thread(tr.d1).start();

         }
 //        System.out.println(System.currentTimeMillis()-time);
     }

     private  void incc() {
 //        synchronized(sb) {
         lock.lock();
         for(int i=0;i<7;i++) {
             char at = "freedom".charAt(i);
             sb.append(at+"");

         }

            System.out.println(Thread.currentThread().getName()+sb.toString());
            sb.delete(0, 7);
 //        }
            lock.unlock();
     }

     private  void decc() {
 //        synchronized(sb) {
         lock.lock();

         for(int i=0;i<7;i++) {
             char at = "freedom".charAt(i);
             sb.append(at+"");

         }

            System.out.println(Thread.currentThread().getName()+sb.toString());
            sb.delete(0, 7);
 //        }
            lock.unlock();

     }

     class inc implements Runnable {
         public void run() {
             // TODO Auto-generated method stub
             for(int i=0; i<100000; i++)
             incc();
         }
     }

     class dec implements Runnable {
         public void run() {
             // TODO Auto-generated method stub
             for(int i=0; i<100000; i++)
             decc();
         }
     }
 }

打印结果各有不同