Search an element of Java ArrayList Example

This Java Example shows how to search an element of java ArrayList object using contains, indexOf and lastIndexOf methods.

import java.util.ArrayList;

public class SearchAnElementInArrayListExample {

 public static void main(String[] args) {

  // create an ArrayList object
  ArrayList arrayList = new ArrayList();

  // Add elements to Arraylist

  arrayList.add("1");
  arrayList.add("2");
  arrayList.add("3");
  arrayList.add("4");
  arrayList.add("5");
  arrayList.add("1");
  arrayList.add("2");

  /**
   * To check whether the specified element exists in Java ArrayList use
   * boolean contains(Object element) method. It returns true if the
   * ArrayList contains the specified objct, false otherwise.
   **/

  boolean blnFound = arrayList.contains("2");
  System.out.println("Does arrayList contain 2 ? " + blnFound);

  /**
   * To get an index of specified element in ArrayList use int
   * indexOf(Object element) method. This method returns the index of the
   * specified element in ArrayList. It returns -1 if not found.
   **/

  int index = arrayList.indexOf("4");
  if (index == -1)
   System.out.println("ArrayList does not contain 4");
  else
   System.out.println("ArrayList contains 4 at index :" + index);

  /**
   * To get last index of specified element in ArrayList use int
   * lastIndexOf(Object element) method. This method returns index of the
   * last occurrence of the specified element in ArrayList. It returns -1
   * if not found.
   **/

  int lastIndex = arrayList.lastIndexOf("1");
  if (lastIndex == -1)
   System.out.println("ArrayList does not contain 1");
  else
   System.out
     .println("Last occurrence of 1 in ArrayList is at index :"
       + lastIndex);

 }
}

The output is:



Does arrayList contain 2 ? true
ArrayList contains 4 at index :3
Last occurrence of 1 in ArrayList is at index :5