The LinkedHashSet is similar to the HashSet, except that LinkedHashSet maintains the insertion order of elements, whereas HashSet does not. Read more about LinkedHashSet here. The removeAll method removes all the elements of the passed collection from the LinkedHashSet, if present.
boolean removeAll(Collection<?> c)
The removeAll method takes the collection object to be removed from the set as an argument.
removeAll returns true if the set changes as a result of the call, meaning that any one of the elements from the collection is removed from the set. Otherwise, the method returns false.
import java.util.LinkedHashSet;import java.util.ArrayList;class RemoveAll {public static void main( String args[] ) {LinkedHashSet<Integer> set = new LinkedHashSet<>();set.add(1);set.add(2);set.add(3);ArrayList<Integer> list = new ArrayList<>();list.add(1);list.add(4);System.out.println("The set is "+ set);System.out.println("The list is "+ list);System.out.println("\nCalling set.removeAll(list). Is set changed - " + set.removeAll(list));System.out.println("\nThe set is "+ set);}}
In the code snippet above, we:
Lines 1-2: Import the LinkedHashSet and ArrayList class.
Lines 5-8: Create a new LinkedHashSet object with the name set and use the add method to add three elements, 1, 2, and 3, to the set object.
Lines 9-11: Create a new ArrayList object with the name list and use the add method to add two elements, 1 and 4, to the list object.
Line 15: Use the removeAll method to remove all the elements of the list from the set. The element 1 in the list is present in the set, so it is removed. The element 4 is not present in the set, so it is not removed. After calling the removeAll method, the content of the set object changes, so the method returns true.