Vector addAll() Method in Java

• java.util.Vector.addAll(Collection C): This method is used to append all of the elements from the collection passed as a parameter to this function to the end of a vector keeping in mind the order of return by the collection’s iterator.

  Syntax:

  boolean addAll(Collection C)

  Parameters: The method accepts a mandatory parameter C which is a collection of ArrayList. It is the collection whose elements are needed to be appended at the end of the vector.

  Return Value: The method returns True if at least one action of append is performed, else False.

  Below program illustrate the Java.util.Vector.addAll() method:

  // Java code to illustrate boolean addAll()
  import java.util.*;
  import java.util.ArrayList;
  
  public class GFG {
      public static void main(String args[])
      {
  
          // Creating an empty Vector
          Vector<String> vt = new Vector<String>();
  
          // Use add() method to add elements in the Vector
          vt.add("Geeks");
          vt.add("for");
          vt.add("Geeks");
          vt.add("10");
          vt.add("20");
  
          // A collection is created
          Collection<String> c = new ArrayList<String>();
          c.add("A");
          c.add("Computer");
          c.add("Portal");
          c.add("for");
          c.add("Geeks");
  
          // Displaying the Vector
          System.out.println("The Vector is: " + vt);
  
          // Appending the collection to the vector
          vt.addAll(c);
  
          // Clearing the vector using clear() and displaying
          System.out.println("The new vector is: " + vt);
      }
  }
  Output:

  The Vector is: [Geeks, for, Geeks, 10, 20]
  The new vector is: [Geeks, for, Geeks, 10, 20, A, Computer, Portal, for, Geeks]
  

• java.util.Vector.addAll(int index, Collection C): This method is used to append all of the elements from the collection passed as a parameter to this function at a specific index or position of a vector.

  Syntax:

  boolean addAll(int index, Collection C)

  Parameters: This function accepts two parameters as shown in the above syntax and are described below.

  • index: This parameter is of integer datatype and specifies the position in the vector starting from where the elements from the container will be inserted.
  • C: It is a collection of ArrayList. It is the collection whose elements are needed to be appended.

  Return Value: The method returns True if at least one action of append is performed, else False.

  Below program illustrate the Java.util.Vector.addAll() method:

  // Java code to illustrate boolean addAll()
  import java.util.*;
  import java.util.ArrayList;
  
  public class GFG {
      public static void main(String args[])
      {
          // Creating an empty Vector
          Vector<String> vt = new Vector<String>();
  
          // Use add() method to add elements in the Vector
          vt.add("Geeks");
          vt.add("for");
          vt.add("Geeks");
          vt.add("10");
          vt.add("20");
  
          // A collection is created
          Collection<String> c = new ArrayList<String>();
          c.add("A");
          c.add("Computer");
          c.add("Portal");
          c.add("for");
          c.add("Geeks");
  
          // Displaying the Vector
          System.out.println("The Vector is: " + vt);
  
          // Appending the collection to the vector
          vt.addAll(1, c);
  
          // Clearing the vector using clear() and displaying
          System.out.println("The new vector is: " + vt);
      }
  }
  Output:

  The Vector is: [Geeks, for, Geeks, 10, 20]
  The new vector is: [Geeks, A, Computer, Portal, for, Geeks, for, Geeks, 10, 20]