1. Using threads on your application:
Users expect programs to achieve strong performance. One way to accomplish that task is to use threads.
A thread is an independent path of execution through program code. Threads benefit GUI-based programs because they allow those programs to remain responsive to users while performing other tasks.
In addition, threaded programs typically finish faster than their non-threaded counterparts. This is especially true of threads running on a multiprocessor machine, where each thread has its own processor.

2. Avoid multithreaded problems:

• lock
• race condition
• semaphores
• deadlock
• inaccessible threads
• blocking I/O

3. Utilize threads:

• synchronized
• the wait/notify mechanism
• size thread pool
• use JDK 5 java.util.concurrent
• exploring thread groups, volatility, thread-local variables, timers
• use JDK 5 java.nio for non-blocking I/O

4. Offline Concurrency Patterns: Optimistic Offline Lock, Pessimistic Offline Lock

Ref:
Java Performance Tuning
Solving common Java EE performance problems
Achieve Strong Performance with Threads