The java.util.NavigableSet.addAll(Collection C) method is used to append all of the elements from the mentioned collection to the existing NavigableSet. The elements are added randomly 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 NavigableSet.
Return Value: The method returns true if it successfully appends the elements of the collection C to this NavigableSet otherwise it returns False.
Note: The addAll() method of NavigableSet interface in Java is inherited from the Set interface.
Below programs illustrate the Java.util.NavigableSet.addAll() method:
Program 1 : Appending a tree NavigableSet.
// Java code to illustrate addAll()import java.io.*;import java.util.*;  public class TreeNavigableSetDemo {    public static void main(String args[])    {        // Creating an empty NavigableSet        NavigableSet<String> st1 = new TreeSet<String>();          // Use add() method to add elements        // into the NavigableSet        st1.add("Welcome");        st1.add("To");        st1.add("Geeks");        st1.add("4");        st1.add("Geeks");        st1.add("TreeNavigableSet");          // Displaying the NavigableSet        System.out.println("NavigableSet: " + st1);          // Creating another NavigableSet        NavigableSet<String> st2 = new TreeSet<String>();          // Use add() method to add elements        // into the NavigableSet        st2.add("Hello");        st2.add("World");          // Using addAll() method to Append        st1.addAll(st2);          // Displaying the final NavigableSet        System.out.println("NavigableSet: " + st1);    }} |
Output:
NavigableSet: [4, Geeks, To, TreeNavigableSet, Welcome] NavigableSet: [4, Geeks, Hello, To, TreeNavigableSet, Welcome, World]
Program 2 : Appending an ArrayList.
// Java code to illustrate addAll()import java.io.*;import java.util.*;  public class NavigableSetDemo {    public static void main(String args[])    {        // Creating an empty NavigableSet        NavigableSet<String> st1 = new TreeSet<String>();          // Use add() method to add elements        // into the NavigableSet        st1.add("Welcome");        st1.add("To");        st1.add("Geeks");        st1.add("4");        st1.add("Geeks");        st1.add("NavigableSet");          // Displaying the NavigableSet        System.out.println("Initial NavigableSet: " + st1);          // An array collection is created        ArrayList<String> collect = new ArrayList<String>();        collect.add("A");        collect.add("Computer");        collect.add("Portal");          // Using addAll() method to Append        st1.addAll(collect);          // Displaying the final NavigableSet        System.out.println("Final NavigableSet: " + st1);    }} |
Output:
Initial NavigableSet: [4, Geeks, NavigableSet, To, Welcome] Final NavigableSet: [4, A, Computer, Geeks, NavigableSet, Portal, To, Welcome]
