ThreadLocal

The benefits of ThreadLocalThreadLocal offers a number of benefits. It is often the easiest way to render a stateful class thread-safe, or to encapsulate non-thread-safe classes so that they can safely be used in multithreaded environments. Using ThreadLocal allows us to bypass the complexity of determining when to synchronize in order to achieve thread-safety, and it improves scalability because it doesn't require any synchronization. In addition to simplicity, using ThreadLocal to store a per-thread-singleton or per-thread context information has a valuable documentation perk -- by using a ThreadLocal, it's clear that the object stored in the ThreadLocal is not shared between threads, simplifying the task of determining whether a class is thread-safe or not.