Java: Insert an element into the array list at the first position

Java Collection, ArrayList Exercises: Exercise-3 with Solution

Write a Java program to insert an element into the array list at the first position.

Pictorial Presentation:

Java Collection, ArrayList Exercises: Insert an element into the array list at the first position

Sample Solution:-

Java Code:

import java.util.*;
  public class Exercise3 {
  public static void main(String[] args) {
  // Creae a list and add some colors to the list
  List<String> list_Strings = new ArrayList<String>();
  // Print the list
  // Now insert a color at the first and last position of the list
  list_Strings.add(0, "Pink");
  list_Strings.add(5, "Yellow");
  // Print the list

Sample Output:

Note: Exercise3.java uses unchecked or unsafe operations.              
Note: Recompile with -Xlint:unchecked for details.                     
[Red, Green, Orange, White, Black]                                     
[Pink, Red, Green, Orange, White, Yellow, Black] 


Flowchart: Insert an element into the array list at the first position.

Java Code Editor:

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Java: Tips of the Day

How to convert an iterator to a stream?

One way is to create a Spliterator from the Iterator and use that as a basis for your stream:

Iterator<String> sourceIterator = Arrays.asList("A", "B", "C").iterator();
Stream<String> targetStream = StreamSupport.stream(
          Spliterators.spliteratorUnknownSize(sourceIterator, Spliterator.ORDERED),

An alternative which is maybe more readable is to use an Iterable - and creating an Iterable from an Iterator is very easy with lambdas because Iterable is a functional interface:

Iterator<String> sourceIterator = Arrays.asList("A", "B", "C").iterator();

Iterable<String> iterable = () -> sourceIterator;
Stream<String> targetStream = StreamSupport.stream(iterable.spliterator(), false);

Ref: https://bit.ly/2NQ4lc8


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