Tips for improving the performane of Java applications

Submitted by loner on 27 October, 2008 - 1:13pm

Use Native Methods: The small amount of overheads caused by JNI is usually outweighed by the improved speed of the native function
Use Buffering on I/O Operations: BufferedInputStream, BufferedOutputStream, BufferedReader, BufferedWriter reduce the number of I/O operations to be performed.
Avoid Creating New Objects: Reuse objects as much as possible. The more objects, the more memory to create/store them.
Use StringBuffer instead of String Concatenations
Avoid Synchronized Methods and Blocks
Use ArrayList and HashMap instead of Vector and Hashtable: Vector and Hashtable are heavily synchronized for thread safety, while ArrayList and HashMap (which provide similar functionality) are not. You can make these Collection classes thread safe by calling static methods within the Collection class that create a thread-safe wrapper around a collection.
Use Resource Pooling for Threads, Databases and Network connections
Make Methods Final, Static, Private: These enable static binding, which is faster than dynamic binding.
Minimise Subclasses and Method Overriding