# How to create executable JAR

### Intro:-    
Jar files (Java ARchive files) is a collection of multiple Java class files.  A jar is an archiving format that  stores directories and source files. And can be run as an executable  file.A JAR (Java ARchive) is a way of packaging together all of the resources associated with a program (class files, images, sounds, etc.). Jar files can be distributed as a single executable file, which save disk space and ease download process.    

### Task:-    
You are packaging and executing a spring boot app in to JAR         

### Software Requirements:-    

Ubuntu-20.04 +jit [linux-x86_64]   
Open Jdk 8   
Spring Boot 2.2    

### Level:-      
Beginner   

### Prerequisite:-    
Knowledge of core java and text editor    

### Step 1:-    
Using Spring Initializr(https://start.spring.io/) download starter app by filling required parameters. Unzip the folder at your computer.        

### Step 2:-    
Add  JAR in your **pom.xml**       

`<packaging>jar</packaging>`

![jarpom.png](https://cdn.hashnode.com/res/hashnode/image/upload/v1628312437853/meWf9prfQ.png)   
`Make sure your pom.xml also contain spring boot plugin`   
 ```   
<plugin>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-maven-plugin</artifactId>
 </plugin>    ```

![pluginpom.png](https://cdn.hashnode.com/res/hashnode/image/upload/v1628312570988/_b5Fyr4b5.png)
    
### Step 3:-    
Run command: `$ mvn clean package`  from terminal    

### Step 4:-     
  

previous command will make target folder, in which contains two  JAR       
 
 a. **runner-0.0.1-SNAPSHOT.jar**   : This is executable JAR    
b.  **runner-0.0.1-SNAPSHOT.jar.original**  : This is original JAR and not executable.     
### Step 5:-     
Suppose you have following pom.xml file in your spring boot project    
```
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.5.3</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.devnation</groupId>
	<artifactId>runner</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>
	<name>runner</name>
	<description>Demo project for runner</description>
	<properties>
		<java.version>1.8</java.version>
	</properties>
	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

</project>
```   
### Step 6:-    
Run executable JAR as follows    
**$ java -jar target/runner-0.0.1-SNAPSHOT.jar**   

![jarrunner.png](https://cdn.hashnode.com/res/hashnode/image/upload/v1628313073767/yDND7dSqc.png)
Server started.    

### Conclusion:-   
After performing above steps you made a spring boot nano app,which package and execute JAR and by making these app you get acquainted with spring boot basics about packaging and executing JAR .