Map equals() method in Java with Examples - GeeksforGeeks

23 Feb, 2022
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() methodimport 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, "Geeks");        map1.put(15, "4");        map1.put(20, "Geeks");        map1.put(25, "Welcomes");        map1.put(30, "You");          // Mapping string values to int keys        map2.put(10, "Geeks");        map2.put(15, "4");        map2.put(20, "Geeks");        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));    }}
First Map: {20=Geeks, 25=Welcomes, 10=Geeks, 30=You, 15=4}
Second Map: {20=Geeks, 25=Welcomes, 10=Geeks, 30=You, 15=4}
Equality: true

Program 2:
// Java code to illustrate the equals() methodimport 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, "Geeks");        map1.put(15, "four");        map1.put(20, "Geeks");        map1.put(25, "Welcomes");        map1.put(30, "You");          // Mapping string values to int keys for map2        map2.put(10, "Geeks");        map2.put(15, "4");        map2.put(20, "Geeks");        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));    }}
First Map: {20=Geeks, 25=Welcomes, 10=Geeks, 30=You, 15=four}
Second Map: {20=Geek, 25=Welcomes, 10=Geeks, 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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