EntityManager with try-with-resource
try-with-resource is the new feature introduced in Java 1.7 to automatically close a resource after using. It basically helps you to avoid a finally block at the end of the try-catch block to close any resource that needs closing like the BufferedReader. But there's a catch. You can not use any type of resource with a try-with-resource block, only those classes that extend java.lang.AutoCloseable can be used, an interface that has a single method:
Today I was writing a Persistence class that uses javax.persistence.EntityManager. Every time I created an instance of EntityManager, I had to manually close it in a finally block. The EntityManager interface also has a close() method with similar signature as above. Only had there been an alternate EntityManager that extended the AutoCloseable interface, I could have avoided the finally block to close it explicitly. Just a thought!