A container class is a class which is used to hold objects in external storage and memory. A container class work as a generic holder. A container class contains a predefined behavior and a well- known interface. A container class is supporting class whose motive is to hide the topology utilized for maintaining the list of objects in memory. While a container class has a group of mixed objects, container is called a heterogeneous container; while the container is holding a group of objects which are all the similar; the container is called a homogeneous container.