How to Find an Object or a String in an Array using Java

Finding an object or a string within an array using several methods in Java. The contains() method with an ArrayList is used to find whether a certain element exists. This way, we can find for strings or objects within a list.

Finding an object or a string in an Array

The contains() method is part of the ArrayList class and is used to check if a specific element exists in an ArrayList. It returns true if the element is found, otherwise false.

Syntax

The following is the syntax for java.util.ArrayList.contains() method

public boolean contains(Object o)

Example

Following example uses Contains method to search a String in the Array

import java.util.ArrayList;

public class Main {
   public static void main(String[] args) {
      ArrayList objArray = new ArrayList();
      ArrayList objArray2 = new ArrayList();
      objArray2.add(0,"common1");
      objArray2.add(1,"common2");
      objArray2.add(2,"notcommon");
      objArray2.add(3,"notcommon1");
      objArray.add(0,"common1");
      objArray.add(1,"common2");
      System.out.println("Array elements of array1"+objArray);
      System.out.println("Array elements of array2"+objArray2);
      System.out.println("Array 1 contains String common2?? "
         +objArray.contains("common1"));
      System.out.println("Array 2 contains Array1?? "
         +objArray2.contains(objArray) );
   }
}

Output

Array elements of array1[common1, common2]
Array elements of array2[common1, common2, notcommon, notcommon1]
Array 1 contains String common2?? true
Array 2 contains Array1?? false

Explanation

This Java code demonstrates how to search for a string within an ArrayList using the contains() method. Two ArrayList objects, objArray and objArray2, are created, with several string elements added to each. The contents of both lists are printed.