It's all about Java

Java Multi threaded programming basics with Reentrant locks As we have seen in earlier post that implicit locking mechanism achieved using synchronized keyword slows down the application performance. Hence java concurrency api gives explicit locking mechanism to achieve mutual exclusion among shared object. How using explicit locks are better than implicit lock? Explicit lock acquires lock per Thread basis and not per method invoke basis. It is inverse in the case of implicit lock.   If a method is synchronized then every invocation of that method involves acquiring and releasing of lock. This process really slows down the application performance.  Hence it is always good idea to prefer reentrent lock or explicit lock to implicit lock. ReentrantLock is a class available in java.util.concurrency package lock() and unlock() methods are used used to acquire and release the lock. Condition class is used in place of Object class wait(), notifyAll() and notify(). ...

All modern computer hardware architectures and operating systems are capable and optimized for multi processor system and multi threaded system.  Process Vrs Thread: Process is heavy weight where as Thread is light weight. Thread is light weight because process uses it's own address space and thread shares the Process's address space. So Threads are considered to be subset of a process. more over threads consumes less OS resources in terms of physical memory and uses CPU time at most. Junior programmers think concurrency is hard.  Experienced programmers think concurrency is easy.  Senior programmers think concurrency is hard.                                                                                    _ Java Concurrency Essentials by Martin ...

Every Java programmer must read and understand the following books. 1. Effective Java 2. Concurrency in practice Effective Java: This book is authored by Joshua Bloch. He took the major role in authoring the java.util package which is [collection framework] one of the java core libraries. He explains the best practices that every programmer should consider while writing java programs. Some of them are: Contract between hashcode() and equals() of Object class when programmer overrides one of these methods in their classes Exceptions concurrency: Inter thread communication, synchronization etc Immutable Objects The above points are few among others. Concurrency in practice: This book gives complete explanation about how efficient concurrency is achieved in java programs using concurrency utility classes which were introduced in Java 5 version. This book is authored by: Brian Goetz Tim peierls Joshua Bloch Joseph Bowbeer David Holmes and Doug Lea ...

1. Since Swing is not thread safe, it is not at all a good practice to launch a UI Container like JFrame, JDialog etc in main Thread. 2. Doing so leads to incorrect behavior of java GUI. 3. To avoid this, Swing toolkit has predefined API as part of JFC. 4.    a. SwingUtilities.invokeAndWait(Runnable r);        b. SwingUtilities.invokeLater(Runnable r); 5. Which part of the code must be in UI Thread?         a. setVisible(true);         b. show(); [deprecated]  and c. pack();       6. Call to these methods mentioned in 5(a), 5(b), and 5(c) must happen in one of the methods mentioned in point 4(a) and point 4(b). That's enough. :)          Example :                        public static void main(String[] args){                         ...