Question

I have a method and a thread which I’d like to run in the following order: First the method should do something with an object, and then the thread should do something with the object. They share the same object. I have to synchronize them, but I am just meeting with Threads. How can I do that?

private synchronized method()
{
//do something with an object (a field)
}

Runnable ObjectUpdater = new Runnable()
{
//do something with the object after the method has finished 
} 

My code, that somehow manages to freeze my Main thread (where the method is)
My thread code:

private Runnable something = new Runnable(){
synchronized (this){
while (flag == false)
{ try {wait();)
catch (IntExc ie) {e.printStackTrace...}
}
//here it does its thing
}
setFlag(false);
}
My method code (part of the main thread)
private void Method()
{
//do its thing
setFlag(true); 
notifyAll();
}

Answer 1

To me that is simple questions

” you said that I do not know which is
going to access the object first – the
separate ObjectUpdater thread, or the
main thread (with the method). If the
separate thread accesses it before the
main thread, that is bad and I don’t
want this to happen”

if you want the main thread method to call first then the objectUpdater thread , have a flag to know whether the method is visited first by main thread ,if it is updater then call wait to this thread , once main finishes it call notify which will run separator thread,
to know which thread is main thread or updater thread , set a name to the thread while creating it. and get the name as Thread.currentThread().getName().