Map equals() method in Java with Examples
The java.util.Map.equals() method in Java is used to check for equality between two maps. It verifies whether the elements of one map passed as a parameter is equal to the elements of this map or not.
Syntax:
boolean equals(object obj)
Parameters: The method accepts one parameter obj of this map type and refers to the map whose equality is to be checked with this map.
Return Value: The method returns true if the equality holds for both the object map else it returns false.
Below programs illustrate the java.util.Map.equals() method:
Program 1:
// Java code to illustrate the equals() method import java.util.*; public class Map_Demo { public static void main(String[] args) { // Creating an empty Map Map<Integer, String> map1 = new HashMap<Integer, String>(); Map<Integer, String> map2 = new HashMap<Integer, String>(); // Mapping string values to int keys map1.put( 10 , "Beginner" ); map1.put( 15 , "4" ); map1.put( 20 , "Beginner" ); map1.put( 25 , "Welcomes" ); map1.put( 30 , "You" ); // Mapping string values to int keys map2.put( 10 , "Beginner" ); map2.put( 15 , "4" ); map2.put( 20 , "Beginner" ); map2.put( 25 , "Welcomes" ); map2.put( 30 , "You" ); // Displaying the Map1 System.out.println( "First Map: " + map1); // Displaying the Map2 System.out.println( "Second Map: " + map2); // Checking the equality System.out.println( "Equality: " + map1.equals(map2)); } } |
Output:
First Map: {20=Beginner, 25=Welcomes, 10=Beginner, 30=You, 15=4} Second Map: {20=Beginner, 25=Welcomes, 10=Beginner, 30=You, 15=4} Equality: true
Program 2:
// Java code to illustrate the equals() method import java.util.*; public class Map_Demo { public static void main(String[] args) { // Creating an empty Map Map<Integer, String> map1 = new HashMap<Integer, String>(); Map<Integer, String> map2 = new HashMap<Integer, String>(); // Mapping string values to int keys for map1 map1.put( 10 , "Beginner" ); map1.put( 15 , "four" ); map1.put( 20 , "Beginner" ); map1.put( 25 , "Welcomes" ); map1.put( 30 , "You" ); // Mapping string values to int keys for map2 map2.put( 10 , "Beginner" ); map2.put( 15 , "4" ); map2.put( 20 , "Beginner" ); map2.put( 25 , "Welcomes" ); map2.put( 30 , "You" ); // Displaying the map 1 System.out.println( "First Map: " + map1); // Displaying the map 2 System.out.println( "Second Map: " + map2); // Displaying the equality System.out.println( "Equality: " + map1.equals(map2)); } } |
Output:
First Map: {20=Beginner, 25=Welcomes, 10=Beginner, 30=You, 15=four} Second Map: {20=Geek, 25=Welcomes, 10=Beginner, 30=You, 15=4} Equality: false
Reference: https://docs.oracle.com/javase/7/docs/api/java/util/Map.html#equals(java.lang.Object)
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