Java Collection Interface Example

Here are the key points about Collection interface:

• If we want to represent a group of individual objects as a single entity then we should go for collections.

• Collection Interface is considered as the root interface of the Collection Framework.

• Collection Interface defines the most common methods which are applicable for any collection object.

• List, Queue, and Set are all subinterfaces of Collection interface. 

• JDK does not provide any direct implementations of this interface. But, JDK provides direct implementations of it’s sub-interfaces.

Collection Interface Example

The following example demonstrates the usage of important Collection interface methods:

package com.java.collections.interfaces;

import java.util.ArrayList;
import java.util.Collection;

public class CollectionDemo {

    public static void main(String[] args) {

        Collection < String > fruitCollection = new ArrayList < > ();
        fruitCollection.add("banana");
        fruitCollection.add("apple");
        fruitCollection.add("mango");
        System.out.println(fruitCollection);

        fruitCollection.remove("banana");
        System.out.println(fruitCollection);

        System.out.println(fruitCollection.contains("apple"));

        fruitCollection.forEach((element) - > {
            System.out.println(element);
        });

        fruitCollection.clear();

        System.out.println(fruitCollection);
    }
}

Output

[banana, apple, mango]
[apple, mango]
true
apple
mango
[]