- Java.util Package Classes
- Java.util - Home
- Java.util - ArrayDeque
- Java.util - ArrayList
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- Java.util - BitSet
- Java.util - Calendar
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- Java.util - EnumMap
- Java.util - EnumSet
- Java.util - Formatter
- Java.util - GregorianCalendar
- Java.util - HashMap
- Java.util - HashSet
- Java.util - Hashtable
- Java.util - IdentityHashMap
- Java.util - LinkedHashMap
- Java.util - LinkedHashSet
- Java.util - LinkedList
- Java.util - ListResourceBundle
- Java.util - Locale
- Java.util - Observable
- Java.util - PriorityQueue
- Java.util - Properties
- Java.util - PropertyPermission
- Java.util - PropertyResourceBundle
- Java.util - Random
- Java.util - ResourceBundle
- Java.util - ResourceBundle.Control
- Java.util - Scanner
- Java.util - ServiceLoader
- Java.util - SimpleTimeZone
- Java.util - Stack
- Java.util - StringTokenizer
- Java.util - Timer
- Java.util - TimerTask
- Java.util - TimeZone
- Java.util - TreeMap
- Java.util - TreeSet
- Java.util - UUID
- Java.util - Vector
- Java.util - WeakHashMap
- Java.util Package Extras
- Java.util - Interfaces
- Java.util - Exceptions
- Java.util - Enumerations
- Java.util Useful Resources
- Java.util - Useful Resources
- Java.util - Discussion
Java LinkedList clear() Method
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
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