Java Unmodifiable SortedMap and SortedSet Example
January 25, 2020
Collections have some static methods that return unmodifiable view for the specified object and the returned instance will be read-only and if we try to modify, it will throw UnsupportedOperationException. Find these static methods.
unmodifiableCollection(): We pass any collection instance and the method returns unmodifiable view for the specified collection object.
unmodifiableList(): It returns an unmodifiable
List.
unmodifiableMap(): It returns an unmodifiable
Map.
unmodifiableSet(): It returns an unmodifiable
Set.
unmodifiableSortedMap(): It returns an unmodifiable
SortedMap.
unmodifiableSortedSet(): It returns an unmodifiable
SortedSet().
Find the example for
unmodifiableSortedMap(), unmodifiableSortedSet() and unmodifiableCollection() methods.
Collections.unmodifiableSortedMap
UnmodifiableSortedMapDemo.java
package com.concretepage.util;
import java.util.Collections;
import java.util.Iterator;
import java.util.Set;
import java.util.SortedMap;
import java.util.TreeMap;
public class UnmodifiableSortedMapDemo {
public static void main(String[] args) {
SortedMap<Integer, String> modifiable = new TreeMap<>();
modifiable.put(1, "AAAA");
SortedMap<Integer, String> unmodifiable = Collections.unmodifiableSortedMap(modifiable);
try {
unmodifiable.put(2, "BBBB");; //will throw error
}catch(UnsupportedOperationException e) {
System.out.println("UnsupportedOperationException-----");
}
Set<Integer> set = unmodifiable.keySet();
Iterator<Integer> ite = set.iterator();
while(ite.hasNext()){
System.out.println(unmodifiable.get(ite.next()));
}
}
}
UnsupportedOperationException----- AAAA
Collections.unmodifiableSortedSet
UnmodifiableSortedSetDemo.java
package com.concretepage.util;
import java.util.Collections;
import java.util.SortedSet;
import java.util.TreeSet;
public class UnmodifiableSortedSetDemo {
public static void main(String[] args) {
SortedSet<String> modifiable = new TreeSet<>();
modifiable.add("1111");
SortedSet<String> unmodifiable = Collections.unmodifiableSortedSet(modifiable);
try {
unmodifiable.add("2222"); //will throw error
}catch(UnsupportedOperationException e) {
System.out.println("UnsupportedOperationException-----");
}
for(String s : unmodifiable){
System.out.println(s);
}
}
}
UnsupportedOperationException----- 1111
Collections.unmodifiableCollection
UnmodifiableCollectionDemo.java
package com.concretepage.util;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
public class UnmodifiableCollectionDemo {
public static void main(String[] args) {
Collection<String> modifiable = new ArrayList<>();
modifiable.add("1111");
Collection<String> unmodifiable = Collections.unmodifiableCollection(modifiable);
try {
unmodifiable.add("2222"); //will throw error
}catch(UnsupportedOperationException e) {
System.out.println("UnsupportedOperationException-----");
}
for(String s : unmodifiable){
System.out.println(s);
}
}
}
UnsupportedOperationException----- 1111
