The equals() method of java.util.AbstractList class is used to compare the specified object with this list for equality. Returns true if and only if the specified object is also a list, both lists have the same size, and all corresponding pairs of elements in the two lists are equal. (Two elements e1 and e2 are equal if (e1==null ? e2==null : e1.equals(e2)).) In other words, two lists are defined to be equal if they contain the same elements in the same order.
Syntax:
public boolean equals(Object o)
Parameters: This method takes the object o as a parameter to be compared for equality with this list.
Returns Value: This method returns true if the specified object is equal to this list.
Below are the examples to illustrate the equals() method.
Example 1:
// Java program to demonstrate// equals() method// for String value import java.util.*; public class GFG1 { public static void main(String[] argv) throws Exception { try { // Creating object of AbstractList<String> AbstractList<String> arrlist1 = new ArrayList<String>(); // Populating arrlist1 arrlist1.add("A"); arrlist1.add("B"); arrlist1.add("C"); arrlist1.add("D"); arrlist1.add("E"); // print arrlist1 System.out.println("First ArrayListlist : " + arrlist1); // Creating another object of AbstractList<String> AbstractList<String> arrlist2 = new ArrayList<String>(); // Populating arrlist2 arrlist2.add("A"); arrlist2.add("B"); arrlist2.add("C"); arrlist2.add("D"); arrlist2.add("E"); // print arrlist2 System.out.println("Second ArrayList : " + arrlist2); // comparing first ArrayList to another // using equals() method boolean value = arrlist1.equals(arrlist2); // print the value System.out.println("Are both list equal : " + value); } catch (NullPointerException e) { System.out.println("Exception thrown : " + e); } }} |
Output:
First ArrayListlist : [A, B, C, D, E] Second ArrayList : [A, B, C, D, E] Are both list equal : true
Example 2:
// Java program to demonstrate// equals() method// for Integer value import java.util.*; public class GFG1 { public static void main(String[] argv) throws Exception { try { // Creating object of AbstractList<Integer> AbstractList<Integer> arrlist1 = new ArrayList<Integer>(); // Populating arrlist1 arrlist1.add(10); arrlist1.add(20); arrlist1.add(30); arrlist1.add(40); arrlist1.add(50); // print arrlist1 System.out.println("First ArrayListlist : " + arrlist1); // Creating another object of AbstractList<Integer> AbstractList<Integer> arrlist2 = new ArrayList<Integer>(); // Populating arrlist2 arrlist2.add(10); arrlist2.add(20); arrlist2.add(30); // print arrlist2 System.out.println("Second ArrayList : " + arrlist2); // comparing first ArrayList to another // using equals() method boolean value = arrlist1.equals(arrlist2); // print the value System.out.println("Are both list equal : " + value); } catch (NullPointerException e) { System.out.println("Exception thrown : " + e); } }} |
Output:
First ArrayListlist : [10, 20, 30, 40, 50] Second ArrayList : [10, 20, 30] Are both list equal : false
