Features

• No Singleton
• Thread Safe
• Leak detection
• Daemon thread for new connections and closing connections.
• Timer for killing all connections. Recreates automatically if used again.
• Another pooling named "PoolingFreshing" for setting how many times the same connection will be used.
• 'DriverManager.getConnection' method can be overridden.
• getConnection could cause wait/stuck situations. Will create another connection exceeding the total connections. (Force New on Stuck setting)
• ClosePool will try to close leaked connections.

Know issues

• For JTDS the "isValid" method does not work. So overwrite it.
• Some databases are automatically set to "Auto Commit". Therefore, you may need to disable it manually if required.

See Settings in the Class

See settings in the constructor

Why?

• Why was this project created? In an older project, this solution was used because there was a bug in the cluster where, occasionally, the connection with jTDS would become invalid.

• Singletons are not purely object-oriented and can cause permanent memory leaks. In some situations, reading too many database records could be a significant problem.

• To protect the copyright of the solution (as well as all the other contributions I added to the repository).

• For the simplicity of adding the solution to the project, inspired by this class here: https://gist.github.com/frkr/d1d4707d094bb61ac3abfa06600b29f1

Finally, in hypothetical scenarios where performance is needed, this application has already been tested in critical scenarios.

Best features

The main reason I keep looking at this project is the use of Proxy Class, Autocloseable and how to use Stacktrace to your advantage to detect problems (used to know where the leak is)