Java Enhanced For Loop(a.k.a for-each loop)

source: https://www.javatpoint.com/for-each-loop

Syntax

for(data_type variable : array | collection){  
//body of for-each loop  
}  

Example: Traversing the collection elements

import java.util.*;
class ForEachExample{
    public static void main(String[] args){
        //Creating a list of elements
        ArrayList<String> list= new ArrayList<>();
        list.add("vimal");
        list.add("sonoo");
        list.add("ratan");
        //traversing the list using for-each loop
        for(String s:list){
            System.out.println(s);
        }
        /* Output:
        vimal
        sonoo
        ratan
        */

    }
    
}  

A collection — sometimes called a container — is simply an object that groups multiple elements into a single unit. Collections are used to store, retrieve, manipulate, and communicate aggregate data.

Java collections framework

source: https://docs.oracle.com/javase/tutorial/collections/intro/index.html
source2: https://www.javatpoint.com/collections-in-java

A collections framework is a unified architecture for representing and manipulating collections. All collections frameworks contain the following:

• Interfaces: These are abstract data types that represent collections. Interfaces allow collections to be manipulated independently of the details of their representation. In object-oriented languages, interfaces generally form a hierarchy.
• Implementations: These are the concrete implementations of the collection interfaces. In essence, they are reusable data structures.
• Algorithms: These are the methods that perform useful computations, such as searching and sorting, on objects that implement collection interfaces. The algorithms are said to be polymorphic: that is, the same method can be used on many different implementations of the appropriate collection interface. In essence, algorithms are reusable functionality.

Summary of Interfaces

The core collection interfaces are the foundation of the Java Collections Framework.
The Java Collections Framework hierarchy consists of two distinct interface trees:

• The first tree starts with the Collection interface, which provides for the basic functionality used by all collections, such as add and remove methods. Its subinterfaces — Set, List, and Queue — provide for more specialized collections.

• The Set interface does not allow duplicate elements. This can be useful for storing collections such as a deck of cards or student records. The Set interface has a subinterface, SortedSet, that provides for ordering of elements in the set.

• The List interface provides for an ordered collection, for situations in which you need precise control over where each element is inserted. You can retrieve elements from a List by their exact position.

• The Queue interface enables additional insertion, extraction, and inspection operations. Elements in a Queue are typically ordered in on a FIFO basis.

• The Deque( double ended queue; deck ) interface enables insertion, deletion, and inspection operations at both the ends. Elements in a Deque can be used in both LIFO and FIFO.

• The second tree starts with the Map interface, which maps keys and values similar to a Hashtable.

• Map's subinterface, SortedMap, maintains its key-value pairs in ascending order or in an order specified by a Comparator.

These interfaces allow collections to be manipulated independently of the details of their representation.