How to iterate List in Java

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In this topic, we are going to learn to iterate the List in Java. A List is an interface that is available in java.util package. These are the following ways to iterate the List:
• Using For loop
• Using For-each loop
• Using While loop
• Using Iterator
• Using ListIterator
• Using Lambda Expression
• Using stream.forEach()

Using For loop

Example

import java.util.List;
import java.util.ArrayList;
public class Test {
public static void main(String args[]) {
//Creating an ArrayList
List < String > listofP = new ArrayList < String > ();
//Adding elements to the List
listofP.add("Peter");
listofP.add("Robert");
listofP.add("John");
listofP.add("Parker");
//Using for loop to iterate the elements of the List
for (int p = 0; p < listofP.size(); p++) {
System.out.println(listofP.get(p));
    }
  }
}

Output

Peter
Robert
John
Parker

Using For-each loop

Example

import java.util.List;
import java.util.ArrayList;
public class Test {
public static void main(String args[]){
//Creating an ArrayList
List<String> theList = new ArrayList<String>();
//Adding elements to the List
theList.add("Peter");
theList.add("Robert");
theList.add("John");
theList.add("Parker");
//Using for each loop to iterate the List
for (String name:theList) {
System.out.println(name);
        }
     }
}

Output

Peter
Robert
John
Parker

Using While loop

Example

import java.util.List;
import java.util.ArrayList;
public class Test {
public static void main(String args[]){
//Creating an ArrayList
List<String> theList = new ArrayList<String>();
//Adding elements to the List
theList.add("Peter"); 
theList.add("Robert");
theList.add("John");
theList.add("Parker");
int i=0;
//Using while loop to iterate the List
while(i<theList.size()) {
System.out.println(theList.get(i));
i++;
        }
    }
}

Output

Peter
Robert
John
Parker

Using Iterator

Example

import java.util.List;
import java.util.ArrayList;
import java.util.Iterator;
public class Test {
public static void main(String args[]){
//Creating an ArrayList
List<String> theList = new ArrayList<String>();
//Adding elements to the List
theList.add("Peter");
theList.add("Robert");
theList.add("John");
theList.add("Parker");
int i=0;
//Using Iterator to iterate the List
Iterator<String> it = theList.iterator();
while(it.hasNext()) {
System.out.println(it.next());
      }
    }
}

Output

Peter
Robert
John
Parker

Using ListIterator

Example

import java.util.List;
import java.util.ArrayList;
import java.util.ListIterator;
public class Test {
public static void main(String args[]){
//Creating a ArrayList
List<String> theList = new ArrayList<String>();
//Adding elements to the List
theList.add("Peter");
theList.add("Robert");
theList.add("John");
theList.add("Parker");
//List Iterator 
ListIterator<String> it = theList.listIterator();
//Using List Iterator to iterate the List
while(it.hasNext()) {
System.out.println(it.next());
       }
   }
}

Output

Peter
Robert
John
Parker

Using Lambda expression

Example

import java.util.List;
import java.util.ArrayList;
public class Test {
public static void main(String args[]){
//Creating an ArrayList
List<String> theList = new ArrayList<String>();
//Adding elements to the List
theList.add("Peter");
theList.add("Robert");
theList.add("John");
theList.add("Parker");
//Using Lambda Expression to iterate the List
theList.forEach(
(name) -> { System.out.println(name); });
    }
}

Output

Peter
Robert
John
Parker

Using stream.forEach()

Example

import java.util.List;
import java.util.ArrayList;
public class Test {
public static void main(String args[]){
//Creating an ArrayList
List<String> theList = new ArrayList<String>();
//Adding elements to the List
theList.add("Peter");
theList.add("Robert");
theList.add("John");
theList.add("Parker");
//Using stream.forEach() to iterate the List
theList.stream().forEach(
(name) -> System.out.println(name));
   }
}

Output

Peter
Robert
John
Parker

Conclusion

In this topic, we learnt how to iterate the List in several ways in Java.

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