Optimize static import assist in Eclipse

In order to make eclipse can auto-import Static methods, we need to make a little config in Eclipse. This article shows how to make the config in Eclipse to make auto-import for static methos works. Also this article list some classes you may need to set in Eclipse useful for your real projects. 1....

Break down package java.util.stream

Stream processing is significant feature of Java 8. In api level, it falls into package java.util.stream. By breaking down the package, you can get a whole view of how the stream api works. Steam introduces map-reduce similar functions to Java. The article is based on Java 8. 1. Hierarchy The above...

Method Reference in Java 8

In java 8 method reference is introduced as a helper for the outstanding feature, Lambda Expression.  In some cases a lambda expression does nothing but to call an exsting method.  Method reference let you make this kind of lambda expression cleaner and shorter. Let see an example, suppose we have a stream created from a User list. The class User has a int field call age with getter and...

Why DAO or Respository bean can be singleton in Spring

This question based on one fact: instance of javax.persistence.EntityManager is NOT thread-safe. Then how does spring handle concurrency on singleton DAO object. Suppose we have a simple DAO bean  looks like below, used in a concurrent scenario, such as in a web application.import javax.persistence.EntityManager; import javax.persistence.PersistenceContext; import javax.transaction.Transactional; import...