Code & Application server related performance issues in J2EE

In J2EE environment, there are some common Code related or Application server related problems. It include:

Code related problems:
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1. Slow Methods
a. Consistently Slow Methods
b. Intermittently Slow Methods
2. Synchronization Problems
3. Memory Problems
4. Coding Practices, such as using exceptions as a means to transfer control in the applications

Application server configuration problems:
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1. JDBC Connection Pool size
2. JVM Heap size
3. Thread Pool size