Java线程wait（）notify（）在一个方法中

Question

public class Signal2NoiseRatio
{
    public ImagePlus SingleSNR(ImagePlus imagePlus) throws InterruptedException
    {

        new Thread()
        { 
          @Override public void run() 
          { 
              for (int i = 0; i <= 1; i++)
              { 
                  System.out.println("in queue"+i);
              }

              synchronized( this ) 
              { 
                  this.notify(); 
              }
            } 
        }.start();


        synchronized (this) 
        {
        this.wait();
        }


        return imagePlusToProcess;
    }
}

notify() does not reach wait() .

what's wrong here?

It is essential for me that both synchonized methods in this one method are implemented.

the main thread perform a frame which presents an image in it. Is it possible that the wait() method leads the frame to a white window?

Answer 1

this in the SingleSNR method and this in the overridden run method are not the same object (inside run , this refers to the anonymous subclass of Thread ). You need to make sure you are notifying the same object you wait for, which is available as Signal2NoiseRatio.this :

      @Override public void run() 
      { 
          for (int i = 0; i <= 1; i++)
          { 
              System.out.println("in queue"+i);
          }

          synchronized( Signal2NoiseRatio.this ) 
          { 
              Signal2NoiseRatio.this.notify(); 
          }
        } 

Answer 2

两个“这个”是不一样的，一个是Signal2NoiseRatio，一个是Thread