The Collection framework is a unified architecture for representing and manipulating collections, enabling collections to be manipulated independently of implementation details.
Uses and advantages of Collection Framework:
- This reduces the efforts of programmers by providing data structures and algorithms, so we do not have to write them.
- This increases performance by providing a high-performance implementation of data structures and algorithms.
- This provides interoperability between unrelated APIs by establishing a common language to pass collections back and forth.
- Reduces the effort required to learn APIs by requiring you to learn multiple ad hoc collection APIs.
- This provides static methods that perform useful functions on collections, such as sorting a list.
- This provides Wrapper implementation which adds functionality, such as synchronization, to other implementations.
And many more advantages it provides for us to use and tackle the problems of development.
Usages: Examples of different types of Interfaces are given below:
- List Interface
- Linked List
- Map Interface
- Stacks
Use Case 1: List Interface
Java
// Java Program that Shows Use of Collection Interface// ArrayListimport java.util.*;class GFG { public static void main(String args[]) { ArrayList<String> list = new ArrayList<String>(); list.add("Geeks"); list.add("areyou"); list.add("working"); list.add("hard?"); Iterator itr = list.iterator(); while (itr.hasNext()) { System.out.println(itr.next()); } }} |
Output
Geeks areyou working hard?
Use Case 2: Linked List
Java
// Java Program that Shows Use of Collection Interface// LinkedListimport java.util.*;// Class testing java Collectionpublic class GFG { // Main driver method public static void main(String args[]) { // Creating a LinkedList LinkedList<String> al = new LinkedList<String>(); // Adding elements to above linked list al.add("Geeks"); al.add("areyou"); al.add("working"); al.add("hard?"); // Iterator Iterator<String> itr = al.iterator(); // Condition check over elements inside using // hasNext() method which holds true till there is // element inside list while (itr.hasNext()) { // Printing elements of LinkedList System.out.println(itr.next()); } }} |
Output
Geeks areyou working hard?
Use Case 3: Map Interface
Java
// Java Program that Shows Use of Collection Interface// Hash-Mapimport java.util.*;public class GFG { // Main driver method public static void main(String[] args) { // Creating a Map Map<Integer, String> map = new HashMap<>(); // Adding elements to map map.put(1, "Geeks"); map.put(2, "are"); map.put(3, "you"); map.put(4, "working"); // Traversing Map // Converting to Set so that traversal is accessed Set set = map.entrySet(); // Iterator Iterator itr = set.iterator(); // Condition check over elements inside using // hasNext() method which holds true till there is // element inside list while (itr.hasNext()) { // Converting to Map.Entry so that we can get // key and value separately Map.Entry entry = (Map.Entry)itr.next(); // Printing elements inside HashMap System.out.println(entry.getKey() + " " + entry.getValue()); } }} |
Output
1 Geeks 2 are 3 you 4 working
Use Case 4: Stacks
Java
// Java Program that Shows Use of Collection Interface// Stackimport java.util.*;public class GFG { // Main driver method public static void main(String args[]) { // Creating a stack in memory Stack<String> stack = new Stack<String>(); // Adding elements to stack stack.push("Geeks"); stack.push("are"); stack.push("you"); stack.push("working"); stack.push("hard?"); // pop() returns all elements of stack stack.pop(); //. iterator Iterator<String> itr = stack.iterator(); // Condition check over elements inside using // hasNext() method which holds true till there is // element inside list while (itr.hasNext()) { // Print all popped elements System.out.println(itr.next()); } }} |
Output
Geeks are you working
