Java Vector clear() Method

---

---

Description

The Java Vector clear() method is used to remove all of the elements from this Vector. The Vector will be empty after this call, unless it throws an exception.

Declaration

Following is the declaration for java.util.Vector.clear() method

public void clear()

Parameters

• This method does not take any parameter as input.

Return Value

The return type is void so it does not return any value.

Exception

UnsupportedOperationException − This exception is thrown if the clear method is not supported by the Collection.

Clearing a Vector of Integer Example

The following example shows the usage of Java Vector clear() method. In this example, we're using Integers. As first step, we're populating the vector object and printing it. Then we're print the size of the vector object and perform clear operation. After clearing, we're printing the size of the vector object which is 0 now.

package com.tutorialspoint;

import java.util.Vector;

public class VectorDemo {
   public static void main(String[] args) {
     
      // create an empty array list
      Vector<Integer> vector = new Vector<>();

      // use add() method to add elements in the vector
      vector.add(20);
      vector.add(30);
      vector.add(10);

      // let us print all the elements available in vector
      System.out.println("Vector = " + vector);    

      // finding size of this vector
      int retval = vector.size();
      System.out.println("Vector consists of "+ retval +" elements");

      System.out.println("Performing clear operation !!");
      vector.clear();
      retval = vector.size();
      System.out.println("Now, Vector consists of "+ retval +" elements");
   }
}   

Output

Let us compile and run the above program, this will produce the following result −

Vector = [20, 30, 10]
Vector consists of 3 elements
Performing clear operation !!
Now, Vector consists of 0 elements

Clearing a Vector of String Example

The following example shows the usage of Java Vector clear() method. In this example, we're using Strings. As first step, we're populating the vector object and printing it. Then we're print the size of the vector object and perform clear operation. After clearing, we're printing the size of the vector object which is 0 now.

package com.tutorialspoint;

import java.util.Vector;

public class VectorDemo {
   public static void main(String[] args) {
     
      // create an empty array list
      Vector<String> vector = new Vector<>();

      // use add() method to add elements in the vector
      vector.add("A");
      vector.add("B");
      vector.add("C");

      // let us print all the elements available in vector
      System.out.println("Vector = " + vector);    

      // finding size of this vector
      int retval = vector.size();
      System.out.println("Vector consists of "+ retval +" elements");

      System.out.println("Performing clear operation !!");
      vector.clear();
      retval = vector.size();
      System.out.println("Now, Vector consists of "+ retval +" elements");
   }
}   

Output

Let us compile and run the above program, this will produce the following result −

Vector = [A, B, C]
Vector consists of 3 elements
Performing clear operation !!
Now, Vector consists of 0 elements

Clearing a Vector of Object Example

The following example shows the usage of Java Vector clear() method. In this example, we're using Student objects. As first step, we're populating the vector object and printing it. Then we're print the size of the vector object and perform clear operation. After clearing, we're printing the size of the vector object which is 0 now.

package com.tutorialspoint;

import java.util.Vector;

public class VectorDemo {
   public static void main(String[] args) {
     
      // create an empty vector
      Vector<Student> vector = new Vector<>();

      // use add() method to add elements in the vector
      vector.add(new Student(1, "Julie"));
      vector.add(new Student(2, "Robert"));
      vector.add(new Student(3, "Adam"));

      // let us print all the elements available in vector
      System.out.println("Vector = " + vector);    

      // finding size of this vector
      int retval = vector.size();
      System.out.println("vector consists of "+ retval +" elements");

      System.out.println("Performing clear operation !!");
      vector.clear();
      retval = vector.size();
      System.out.println("Now, vector consists of "+ retval +" elements");
   } 		
} 

class Student {
   int rollNo;
   String name;

   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
}  

Output

Let us compile and run the above program, this will produce the following result −

Vector = [[ 1, Julie ], [ 2, Robert ], [ 3, Adam ]]
vector consists of 3 elements
Performing clear operation !!
Now, vector consists of 0 elements