synchronization

Specifically, can somebody tell me what is wrong with this piece of code. It should start the threads, so should print "Entering thread.." 5 times and then wait until notifyAll() is called. But, it randomly prints "Entering.." and "Done.." and still keeps waiting on others. public class ThreadTest implements Runnable { private int num; private static Object obj = new Object(); ThreadTest(int n) { num=n; } @Override public void run() { synchronized (obj) { try { System.out.println("Entering thread "+num); obj.wait(); System.out.println("Done Thread "+num); } catch (InterruptedException e) { e

I just found the following OpenGL specification for ARB_map_buffer_range . I'm wondering if it is possible to do non-blocking map calls using this extension? Currently in my application im rendering to an FBO which I then map to a host PBO buffer. glMapBuffer(target_, GL_READ_ONLY); However, the problem with this is that it blocks the rendering thread while transferring the data. I could reduce this issue by pipelining the rendering, but latency is a big issue in my application. My question is whether i can use map_buffer_range with MAP_UNSYNCHRONIZED_BIT and wait for the map operation to

I have implemented a SyncAdapter, AccountManager and private ContentProvider along the lines of the SimpleSyncAdapter sample project in the SDK. It is all working well. Now I want to show a message to the user when new rows have been downloaded from the remote server that have a specific flag set. I need a callback from the SyncAdapter when a Sync has finished so I can do the query and display the message from an activity. I have seen a few questions on StackOverflow discussing this but none with a good answer. How does one listen for progress from Android SyncAdapter? says that the

We can not make constructor synchronized but can write synchronized this inside constructor. In what case such requirement will come ? I am amused. package com.simple; public class Test { public Test() { synchronized (this) { System.out.println("I am called ..."); } } public static void main(String[] args) { Test test=new Test(); System.out.println(""+test); } @Override public String toString() { return "Test []"; } } Well, you could start a new thread within the constructor. It would be highly unusual - and certainly in the code you've provided it would be pointless - but it could happen.