SortedSet removeAll() method in Java with Examples (original) (raw)

Last Updated : 29 Dec, 2021

The removeAll() method of SortedSet interface is used to remove from this SortedSet all of its elements that are contained in the specified collection.
Syntax:

public boolean removeAll(Collection c)

Parameters: This method takes collection c as a parameter containing elements to be removed from this SortedSet.
Returns Value: This method returns true if this set changed as a result of the call.
Exception: This method throws NullPointerException if this set contains a null element and the specified collection does not permit null elements (optional), or if the specified collection is null.
Note: The removeAll() method in SortedSet is inherited from the Set interface in Java.
Below are the examples to illustrate the removeAll() method.
Example 1:

Java `

// Java program to demonstrate // removeAll() method for Integer value

import java.util.*;

public class GFG1 { public static void main(String[] args) throws Exception {

    try {
        // Creating object of SortedSet
        SortedSet<Integer> set1
            = new TreeSet<Integer>();

        // Populating set1
        set1.add(1);
        set1.add(2);
        set1.add(3);
        set1.add(4);
        set1.add(5);

        // print set1
        System.out.println(
            "Set before "
            + "removeAll() operation : "
            + set1);

        // Creating another object of Set
        SortedSet<Integer> set2
            = new TreeSet<Integer>();
        set2.add(1);
        set2.add(2);
        set2.add(3);

        // print set2
        System.out.println(
            "Collection Elements "
            + "to be removed : "
            + set2);

        // Removing elements from set
        // specified in set2
        // using removeAll() method
        set1.removeAll(set2);

        // print set1
        System.out.println(
            "Set after "
            + "removeAll() operation : "
            + set1);
    }

    catch (NullPointerException e) {
        System.out.println("Exception thrown : "
                           + e);
    }
}

}

`

Output:

Set before removeAll() operation : [1, 2, 3, 4, 5] Collection Elements to be removed : [1, 2, 3] Set after removeAll() operation : [4, 5]

Example 2: For NullPointerException.

Java `

// Java program to demonstrate // removeAll() method for Integer value

import java.util.*;

public class GFG1 {

public static void main(String[] args)
    throws Exception
{
    try {

        // Creating object of SortedSet
        SortedSet<Integer> set1
            = new TreeSet<Integer>();

        // Populating set1
        set1.add(1);
        set1.add(2);
        set1.add(3);
        set1.add(4);
        set1.add(5);

        // print set1
        System.out.println(
            "Set before "
            + "removeAll() operation : "
            + set1);

        // Creating another object of SortedSet<Integer>
        SortedSet<Integer> set2 = null;

        // print set2
        System.out.println(
            "Collection Elements"
            + " to be removed : "
            + set2);

        System.out.println(
            "\nTrying to pass "
            + "null as a specified element\n");

        // Removing elements from set
        // specified in set2
        // using removeAll() method
        set1.removeAll(set2);

        // print set1
        System.out.println(
            "Set after "
            + "removeAll() operation : "
            + set1);
    }

    catch (NullPointerException e) {
        System.out.println(e);
    }
}

}

`

Output:

Set before removeAll() operation : [1, 2, 3, 4, 5] Collection Elements to be removed : null

Trying to pass null as a specified element

java.lang.NullPointerException

Reference: https://docs.oracle.com/javase/7/docs/api/java/util/Set.html#removeAll(java.util.Collection)