Autoboxing and Unboxing Conversion with Examples in Java


A quick guide to autoboxing and unboxing concepts in java with example programs.

Autoboxing and Unboxing in Java

Java 1.5 version has introduced Autoboxing and Unboxing in Java.

Autoboxing Conversion :

Converting primitive types to corresponding reference wrapper types called as "Autoboxing" and this happens run time implicitly.

Autoboxing and Unboxing in Java

Following are Autoboxing conversion in Java allow.

1) boolean to type Boolean
2) byte to type Byte
3) short to type Short
4) char to type Character
5) int to type Integer
6) long to type Long
7) float to type Float
8)double to type Double
Boxing conversion may result in an OutOfMemoryError if new instances are created.
If we have int to Integer.. which means first have to allocate memory for int and than boxing conversion to Integer wrapper class instance memory allocation.

Autoboxing Example :

package org.java.w3schools.autoboxing;

public class AutoboxingExample {
    public static void main(String[] args) {

        int i = 100;

        Integer integer = i; // Autoboxing

        double d = 190;

        show(d);  // Autoboxing

    public static void show(Double d) {

        System.out.println("double : " + d);

Unboxing Conversion :

Converting reference types to corresponding primitive types called as "Unboxing" and this also happens runtime implicitly.

Following are Unboxing conversion in Java allow.

1) Boolean to type boolean
2) Byte to type byte
3) Short to type short
4) Character to type char
5) Integer to type int
6) Long to type long
7) Float to type float
8) Double to type double

If reference is null, than unboxing result in NulllPointerEception.

Unboxing Example :

package org.java.w3schools.unboxing;

public class UnboxingExample {

     * @param args
    public static void main(String[] args) {
        Integer integer = new Integer(100);
        int i = integer; // Unboxing

        display(new Boolean(false)); // Unboxing

    public static void display(boolean status) {
        System.out.println("Status :: " + status);


Note: Garbage Collector has to do cleanup boxing cached objects. Good to avoid boxing techniques for error proneing.



About Us

Author: Venkatesh - I love to learn and share the technical stuff.

accumulo,1,ActiveMQ,2,Adsense,1,API,37,ArrayList,18,Arrays,24,Bean Creation,3,Bean Scopes,1,BiConsumer,1,Blogger Tips,1,Books,1,C Programming,1,Collection,8,Collections,37,Collector,1,Command Line,1,Comparator,1,Compile Errors,1,Configurations,7,Constants,1,Control Statements,8,Conversions,6,Core Java,149,Corona India,1,Create,2,CSS,1,Date,3,Date Time API,38,Dictionary,1,Difference,2,Download,1,Eclipse,3,Efficiently,1,Error,1,Errors,1,Exceptions,8,Fast,1,Files,17,Float,1,Font,1,Form,1,Freshers,1,Function,3,Functional Interface,2,Garbage Collector,1,Generics,4,Git,9,Grant,1,Grep,1,HashMap,2,HomeBrew,2,HTML,2,HttpClient,2,Immutable,1,Installation,1,Interview Questions,6,Iterate,2,Jackson API,3,Java,32,Java 10,1,Java 11,6,Java 12,5,Java 13,2,Java 14,2,Java 8,128,Java 8 Difference,2,Java 8 Stream Conversions,4,java 8 Stream Examples,12,Java 9,1,Java Conversions,14,Java Design Patterns,1,Java Files,1,Java Program,3,Java Programs,114,Java Spark,1,java.lang,4,java.util. function,1,JavaScript,1,jQuery,1,Kotlin,11,Kotlin Conversions,6,Kotlin Programs,10,Lambda,2,lang,29,Leap Year,1,live updates,1,LocalDate,1,Logging,1,Mac OS,3,Math,1,Matrix,6,Maven,1,Method References,1,Mockito,1,MongoDB,3,New Features,1,Operations,1,Optional,6,Oracle,5,Oracle 18C,1,Partition,1,Patterns,1,Programs,1,Property,1,Python,2,Quarkus,1,Read,1,Real Time,1,Recursion,2,Remove,2,Rest API,1,Schedules,1,Serialization,1,Servlet,2,Sort,1,Sorting Techniques,8,Spring,2,Spring Boot,23,Spring Email,1,Spring MVC,1,Streams,31,String,61,String Programs,28,String Revese,1,StringBuilder,1,Swing,1,System,1,Tags,1,Threads,11,Tomcat,1,Tomcat 8,1,Troubleshoot,26,Unix,3,Updates,3,util,5,While Loop,1,
JavaProgramTo.com: Autoboxing and Unboxing Conversion with Examples in Java
Autoboxing and Unboxing Conversion with Examples in Java
A quick guide to autoboxing and unboxing concepts in java with example programs.
Loaded All Posts Not found any posts VIEW ALL Readmore Reply Cancel reply Delete By Home PAGES POSTS View All RECOMMENDED FOR YOU LABEL ARCHIVE SEARCH ALL POSTS Not found any post match with your request Back Home Sunday Monday Tuesday Wednesday Thursday Friday Saturday Sun Mon Tue Wed Thu Fri Sat January February March April May June July August September October November December Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec just now 1 minute ago $$1$$ minutes ago 1 hour ago $$1$$ hours ago Yesterday $$1$$ days ago $$1$$ weeks ago more than 5 weeks ago Followers Follow THIS PREMIUM CONTENT IS LOCKED STEP 1: Share to a social network STEP 2: Click the link on your social network Copy All Code Select All Code All codes were copied to your clipboard Can not copy the codes / texts, please press [CTRL]+[C] (or CMD+C with Mac) to copy Table of Content