Do you need to know how to sort Java objects in a collection, array, or map? Here's how to use the Comparable and Comparator interfaces and avoid ClassCastExceptions. Programmers frequently need to ...

Comparable and comparator both are an interface that can be used to sort the elements of the collection. Comparator interface belongs to java.util package while comparable belongs to java.lang package ...

Order has a List of OrderPosition and OderPosition has the attribute oid. oid is @Id attribute of type long. Issueing this query results in an OpenJPA Exception and i really dont want to use some ...