Java Collection iterator() Method

The iterator() method of Java Collection Interface returns an iterator over the elements in this collection.

Syntax

Parameters

Return

The iterator () method returns an iterator over the elements in this collection.

Example 1

import java.util.Collection;
import java.util.Iterator;
import java.util.concurrent.ConcurrentLinkedQueue;
public class JavaCollectionIteratorExample1 {
    static int i = 1;
    public static void main(String[] args) {
        Collection<String> collection = new ConcurrentLinkedQueue<String>();
        collection.add("Ram");
        collection.add("Sham");
        collection.add("Mira");
        collection.add("Rajesh");
        Iterator<String> iterator = collection.iterator();
        //Returns an iterator over the elements
        while (iterator.hasNext()) {
            System.out.println(i++ + "." + iterator.next());
        }
    }
}

Test it Now

Output:

1.Ram
2.Sham
3.Mira
4.Rajesh

Example 2

import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.concurrent.ConcurrentLinkedQueue;
public class JavaCollectionIteratorExample2 {
    public static void main(String[] args) {
        Integer[] val = new Integer[2];
        Collection<Integer> collection = new ConcurrentLinkedQueue<Integer>();
        collection.add(71018);
        collection.add(8000);
        collection.add(1178);
        collection.add(1190);
        //Returns an iterator over the elements
        Iterator<Integer> iterator = collection.iterator();
        while(iterator.hasNext()){
            System.out.println(iterator.next());
            val[0] = Collections.max(collection);
            val[1] = Collections.min(collection);
        }
        System.out.println("Max number = "+ val[0]);
        System.out.println("Min number = "+ val[1]);
    }
}

Test it Now

Output:

71018
8000
1178
1190
Max number = 71018
Min number = 1178

Example 3

import java.util.Collection;
import java.util.Iterator;
import java.util.concurrent.LinkedBlockingDeque;
public class JavaCollectionIteratorExample3 {
    public static void main(String[] args) {
        Collection<Character> collection = new LinkedBlockingDeque<Character>();
        for (char c = 'a'; c <= 'z'; c++) {
            collection.add(c);
        }
        System.out.print("Characters : ");
        System.out.print("[");
        Iterator<Character> iterator = collection.iterator();
        //will return the iterator for all characters
        while (iterator.hasNext()) {
            System.out.print(iterator.next()+" ,");
        }
        System.out.println("]");
    }
}

Test it Now

Output:

Characters : [a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,]

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