EJB 面试题与答案

Question: can we have static initializer Block in EJB?

Answer: Purpose of Static initializer block is to initialize some static fields before any execution of constructor or method or we can say creation of object. According to EJB Spec it�s a violation if static field are used and they are non final .

"EJB Spec":
Enterprise bean are not allowed to read or write the non final fields.

But technically,from the point of java its correct but if in EJB we use static initializer block to initialize static field then because EJB components are used in distributed environment mean to say if single JVM then it will be ok but if run on different JVM then it will be a problem if we change or update the value in on environment then only the instance running on same JVM have new value .that�s why static blocks are avoided and also all static field should be final.
And same thing we can achieve in ejbCreate(), setSessionContext() or setEntityContext() methods.