The addAll(Collection C) method of Java AbstractCollection is used to append all of the elements from a mentioned collection to this collection. The elements are added randomnly without following any specific order.
Syntax:
boolean addAll(Collection C)
Parameters: The parameter C is a collection of any type that is to be added to the collection.
Return Value: The method returns true if it successfully appends the elements of the collection C to the existing collection otherwise it returns False.
Below programs illustrate the AbstractCollection.addAll() method:
Program 1:
// Java code to illustrate addAll() // method of AbstractCollection import java.util.*; import java.util.AbstractCollection; public class AbstractCollectionDemo { public static void main(String args[]) { // Creating an empty collection AbstractCollection<String> abs1 = new TreeSet<String>(); // Use add() method to add // elements into the Collection abs1.add( "Welcome" ); abs1.add( "To" ); abs1.add( "Geeks" ); abs1.add( "4" ); abs1.add( "Geeks" ); abs1.add( "TreeSet" ); // Displaying the Collection System.out.println( "AbstractCollection 1: " + abs1); // Creating anothe Collection AbstractCollection<String> abs2 = new TreeSet<String>(); // Displaying the Collection System.out.println( "AbstractCollection 2: " + abs2); // Using addAll() method to Append abs2.addAll(abs1); // Displaying the Collection System.out.println( "AbstractCollection 2: " + abs2); } } |
AbstractCollection 1: [4, Geeks, To, TreeSet, Welcome] AbstractCollection 2: [] AbstractCollection 2: [4, Geeks, To, TreeSet, Welcome]
Program 2:
// Java code to illustrate addAll() // method of AbstractCollection import java.util.*; import java.util.AbstractCollection; public class AbstractCollectionDemo { public static void main(String args[]) { // Creating an empty collection AbstractCollection<Integer> abs1 = new TreeSet<Integer>(); // Use add() method to add // elements into the Collection abs1.add( 10 ); abs1.add( 20 ); abs1.add( 30 ); abs1.add( 40 ); abs1.add( 50 ); // Displaying the Collection System.out.println( "AbstractCollection 1: " + abs1); // Creating anothe Collection AbstractCollection<Integer> abs2 = new TreeSet<Integer>(); // Displaying the Collection System.out.println( "AbstractCollection 2: " + abs2); // Using addAll() method to Append abs2.addAll(abs1); // Displaying the Collection System.out.println( "AbstractCollection 2: " + abs2); } } |
AbstractCollection 1: [10, 20, 30, 40, 50] AbstractCollection 2: [] AbstractCollection 2: [10, 20, 30, 40, 50]
Attention reader! Don’t stop learning now. Get hold of all the important Java Foundation and Collections concepts with the Fundamentals of Java and Java Collections Course at a student-friendly price and become industry ready.