LinkedHashSet removeIf(Predicate) in Java

removeIf(Predicate): This method is available in java.util.LinkedHashSet class of Java.

Syntax:

boolean java.util.Collection.removeIf(Predicate<? super K> filter)

This method takes one argument. This method removes all of the elements of this collection that satisfy the given predicate.

Parameters: One parameter is required for this method.

filter: a predicate which returns true for elements to be removed.

Returns: true if any elements were removed.

Throws:

1. NullPointerException - if the specified filter is null.

2. UnsupportedOperationException - if elements cannot be removed from this collection.

Approach 1: When no exception

Java

import java.util.LinkedHashSet;
import java.util.function.Predicate;

public class LinkedHashSetremoveIf {
    public static void main(String[] args) {

        LinkedHashSet<Integer> linkedHashSet =
                          new LinkedHashSet<>();

        linkedHashSet.add(10);
        linkedHashSet.add(20);
        linkedHashSet.add(15);
        Predicate<Integer> filter = (i) -> i > 10;
        linkedHashSet.removeIf(filter);

        System.out.println(linkedHashSet);

    }
}

Output:

[10]

Approach 2: NullPointerException 

Java

import java.util.LinkedHashSet;
import java.util.function.Predicate;

public class LinkedHashSetremoveIf {
    public static void main(String[] args) {

        LinkedHashSet<Integer> linkedHashSet =
                              new LinkedHashSet<>();

        linkedHashSet.add(10);
        linkedHashSet.add(20);
        linkedHashSet.add(15);
        Predicate<Integer> filter = null;
        linkedHashSet.removeIf(filter);

        System.out.println(linkedHashSet);

    }
}

Output:

Exception in thread "main" java.lang.NullPointerException
	at java.base/java.util.Objects.requireNonNull(Objects.java:208)
	at java.base/java.util.Collection.removeIf(Collection.java:572)