What is the ArrayList.contains() method in Java?

import java.util.ArrayList;
public class main {
  public static void main(String[] args) {
    // create an array list
    ArrayList<Integer> arrlist = new ArrayList<Integer>(4);
    // populate the list
    arrlist.add(10);
    arrlist.add(20);
    arrlist.add(30);
    arrlist.add(40);  
    // check for presence of an element contained in the list
    boolean retval = arrlist.contains(10); 
      
    if (retval == true) {
      System.out.println("10 is present in the list");
    } else {
      System.out.println("10 is not present in the list");
    }
        
    // check for presence of an element not contained in the list
    boolean retval2 = arrlist.contains(90);
      
    if (retval2 == true) {
      System.out.println("90 is present in the list");
    } else {
      System.out.println("90 is not present in the list");
    }
  }
}

import java.util.Arrays;
public class main {
  public static void main(String[] args) {
    // create an array
    Integer arr[] = { 10, 20, 30, 40 }; 
    // check for presence of an element in the array
    boolean retval = Arrays.asList(arr).contains(10); 
    if (retval == true) {
      System.out.println("10 is present in the Array");
    } else {
      System.out.println("10 is not present in the Array");
    }
        
    // check for presence of an element not in the Array
    boolean retval2 = Arrays.asList(arr).contains(90); 
      
    if (retval2 == true) {
      System.out.println("90 is present in the Array");
    } else {
      System.out.println("90 is not present in the Array");
    }
  }
}