How would you design an object pool in java ?

1. http://stackoverflow.com/questions/1137118/does-this-basic-java-object-pool-work
2. http://www.javaworld.com/javaworld/jw-06-1998/jw-06-object-pool.html
3. http://sourcemaking.com/design_patterns/object_pool/java
4. The basic interface of the object pool should like this
5. public interface ObjectPool<T> {
       T borrowObject();
       void returnObject(T borrowed);
   }
   
6. http://commons.apache.org/pool/