AbstractList equals() method in Java with Examples

Last Updated : 26 Nov, 2018

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

// 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

// 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

AbstractList get() method in Java with Examples

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AbstractList equals() method in Java with Examples

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