Collection Framework Simplified in Java

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Collection is an important concept in java. The collection framework is a part of java.util package.The collection framework defines a set of interfaces and their implementation to manipulate collections. They serve as a container for a group of Objects such as a set of words in a dictionary or a collection of emails etc.The collection framework also allows us to store,retrieve and update a set of objects.
Advantages of collection:

  • It is grow able in nature, based on programmer or application need , this can be increased or decreased.
  • It can hold homogeneous or heterogeneous data
  • Every collection is backed by some data structure [ready made data structure]

To overcome problem of array it is important to use collection.

Collection:  Collection is way of representation of a group of objects as a single entity.In general collection interface is considered as root interface of collection framework.
Collection Framework: It is group of several classes and interfaces which can be used to represent a group of objects a single entity.

So basically a collection is a set of elements. Methods defined in a collection Interface as given as:

add(Object obj);// returns true if the object is added to the specified collection.
adAll(Collection c);//returns true if the objects of the collection c are added to the specified collection.
remove(Object obj);//returns true if the object is removed from the specified collection.
removeAll(Collection c)//returns true if the objects of the collection c are removed from the specified collection.
clear();//removes all elements from the specified collection
contains(Object obj);////returns true if the collection contains the specified object.
containsAll(Collection c);//Returns true if the collection contains all the elements in the specified collection.
equals(Object obj);//Returns true if the specified object matches with the object in the collection.
hashCode();//returns the hashcode of the collection.
isEmpty();//Returns true if the collection is empty.
iterator();Returns iterator over the elements in the collection.
retainAll(Collection c);//Returns true if all the elements in a collection c is retrained in the specified
size();//returns the number of elements in the collection.
toArray();//returns an array containing all of the elements in the collection.
toArray(Object[] object) ;//returns an array of objects if the array contains all the elements in the
//specified collection.

add(),addAll() and remove() modify the collection objects.They may throw an Exception-UnsupportedOperationException when the collection does not support respective operation.
The methods of the collection interface will throw the ClassCastException if we add an incompatible element to a collection.(Some collection may not support null elements.)

See also  Abstract Interface DataInput in Java

Collection is an interface which can be used to represent a group of objects as  a single entity.
Collections is an utility class found in java.util package to define several utility methods for collection objects.
The different frameworks are written below:


The classes available in the collection framework implements the collection interface and the sub Interfaces. These classes also implement Map and Iterator Interfaces.
I am  writing on these one by one.

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One thought on “Collection Framework Simplified in Java

  1. Hi my loved one! I wish to say that this post is awesome, nice written and come with approximately all vital infos. I’d like to see more posts like this .

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