Concurrent Programming and Locking in J2SE 5.0

摘要

In concurrent programming, exclusion refers to any technique that dynamically locks certain blocks of code so multiple threads can't corrupt their shared resources in ways that can cause integrity problems. In Java, exclusion has meant using the synchronized keyword against a method or block of code to control access to an object's lock. Even though synchronization is a simple and concise way of controlling access to critical code, there are some limitations: 1. While a thread is trying to acquire a lock, it can't be interrupted or timed-out. 2. Each lock can only test against a single implicit condition using the wait() and notify() methods, which doesn't give developers much flexibility when trying to react to particular program states.