Java Vector retainAll() Method with Examples

by Online Tutorials Library July 22, 2022

Java Vector retainAll() Method

The retainAll() method of Java Vector class is used to retain only that elements in the vector which are contained in the specified collection. In other words, it removes all elements from this vector that are not contained in the specified collection.

Syntax

Following is the declaration of retainAll() method:

Parameter

Parameter	Description	Required/Optional
c	It is a collection of elements which will be retained in this vector, and all other elements are removed.	Required

Return

The retainAll() method returns true if the vector changed as a result of the call.

Exceptions

NullPointerException– This method has thrown an exception if the vector contains one or more null elements and the specified collection does not support null elements or if the specified collection is null.

Compatibility Version

Java 1.2 and above

Example 1

  import java.util.Vector;  public class VectorRetainAllExample1 {    public static void main(String arg[]) {    //Create an empty Vec1          Vector<Integer> vec1 = new Vector<>();          //Add elements in the Vector1          vec1.add(1);          vec1.add(2);          vec1.add(3);          vec1.add(4);          vec1.add(2);           //Create an empty Vec2          Vector<Integer> vec2 = new Vector<>();          //Add elements in the Vector2          vec2.add(2);          vec2.add(3);           //Displaying the Vector elements                System.out.println(“Values in vector :” +vec1);          //use retainAll() method          vec1.retainAll(vec2);          System.out.println(“Values in vector :” +vec1);    }  }  

Test it Now

Output:

Values in vector :[1, 2, 3, 4, 2]  Values in vector :[2, 3, 2]

Example 2

  import java.util.Vector;  public class VectorRetainAllExample2 {    public static void main(String arg[]) {    //Create an empty Vec1          Vector<String> vec1 = new Vector<String>();          //Add elements in the Vector1          vec1.add(“A”);          vec1.add(“B”);          vec1.add(“C”);          vec1.add(“10”);          vec1.add(“20”);           //Displaying the Vector1 elements          System.out.println(“Vector: ” + vec1);           //Create an empty Vec2          Vector<String> vec2 = new Vector<String>();           //Add elements in the Vector2          vec2.add(“A”);          vec2.add(“B”);          vec2.add(“C”);           //use retainAll() method          boolean changed = vec1.retainAll(vec2);          //Print the result          if (changed)              System.out.println(“Collection retained”);          else              System.out.println(“Collection not retained”);          //Display the final Vector          System.out.println(“Final Vector: ” + vec1);    }  }  

Test it Now

Output:

Vector: [A, B, C, 10, 20]  Collection retained  Final Vector: [A, B, C]

Next TopicJava Vector

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