Iterate a List in Java

By: Dorris Viewed: 150 times  Printer Friendly Format    


This tutorial demonstrates the use of ArrayList, Iterator and a List. There are many ways to iterate a list of objects in Java. This sample program shows you the different ways of iterating through a list in Java.

In java a list object can be iterated in following ways:

  • Using Iterator class
  • With the help of for loop
  • With the help of while loop
  • Java 5 for-each loop

Following example code shows how to iterate a list object:

import java.util.Iterator;
import java.util.List;
import java.util.ArrayList;
 
public class IterateAList {
  public static void main(String[] argv) {
 
                ArrayList arrJavaTechnologies = new ArrayList();

                arrJavaTechnologies.add("JSP");
                arrJavaTechnologies.add("Servlets");
                arrJavaTechnologies.add("EJB");
                arrJavaTechnologies.add("JDBC");
                arrJavaTechnologies.add("JPA");
                arrJavaTechnologies.add("JSF");


                //Iterate  with the help of Iterator class
                System.out.println("Iterating with the help of Iterator class");
                Iterator iterator = arrJavaTechnologies.iterator();
                while(iterator.hasNext()){
                        System.out.println( iterator.next() );
                }

                //Iterate  with the help of for loop
                System.out.println("Iterating with the help of for loop");
                for (int i=0; i< arrJavaTechnologies.size(); i++)
                {
                        System.out.println( arrJavaTechnologies.get(i) );
                }

                //Iterate  with the help of while loop
                System.out.println("Iterating with the help of while loop");
                int j=0; 
                while (j< arrJavaTechnologies.size())
                {
                        System.out.println( arrJavaTechnologies.get(j) );
                        j++;
                }
                //Iterate  with the help of java 5 for-each loop
                System.out.println("Iterate  with the help of java 5 for-each loop");
                for (String element : arrJavaTechnologies) // or sArray
                {
                        System.out.println( element );
                }
 
  }
}


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