Java LinkedList clear() Method

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Description

The Java LinkedList clear() method removes all of the elements from this list.The list will be empty after this call returns.

Declaration

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

public void clear()

Parameters

NA

Return Value

This method does not return any value.

Exception

NA

Clearing a LinkedList of Integer Example

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

package com.tutorialspoint;

import java.util.LinkedList;

public class LinkedListDemo {
   public static void main(String[] args) {
     
      // create an empty linked list
      LinkedList<Integer> linkedList = new LinkedList<>();

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

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

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

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

Output

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

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

Clearing a LinkedList of String Example

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

package com.tutorialspoint;

import java.util.LinkedList;

public class LinkedListDemo {
   public static void main(String[] args) {
     
      // create an empty linked list
      LinkedList<String> linkedList = new LinkedList<>();

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

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

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

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

Output

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

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

Clearing a LinkedList of Object Example

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

package com.tutorialspoint;

import java.util.LinkedList;

public class LinkedListDemo {
   public static void main(String[] args) {
     
      // create an empty linkedList
      LinkedList<Student> linkedList = new LinkedList<>();

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

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

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

      System.out.println("Performing clear operation !!");
      linkedList.clear();
      retval = linkedList.size();
      System.out.println("Now, linkedList 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 −

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