How to make Map Unmodifiable in java collection

Collections class provide a method unmodifiableMap to make our Map unchangeable.
After applying unmodifiableMap() to map if try to put a new value it will throw UnsupportedOperationException.



public class UnmodifiableMapTest {

    public static void main(String[] args) {
      

        Map map=new HashMap();
        map.put(1, "value1");
        map.put(2, "value2");
        Map m=Collections.unmodifiableMap(map);
       
        m.put(3, "value3");
        System.out.println(map);
   
    }

}


Output : -

Exception in thread "main" java.lang.UnsupportedOperationException
    at java.util.Collections$UnmodifiableMap.put(Collections.java:1457)
    at Basic.Animals.main(Animals.java:31)