JAVA - How to create an executable JAR with dependencies using Maven - Learn in 30 Sec from Microsoft Awarded MVP

Maven

Mavenis a powerful project management tool that is based on POM (project object model). It is used for projects build, dependency and documentation.
It simplifies the build process like ANT. But it is too much advanced than ANT.
Current version of Maven is 3.

A JAR (Java ARchive)

JAR is a package file format typically used to aggregate many Java class files and associated metadata and resources (text, images, etc.) into one file for distribution.

TO CREATE A JAR FILE WITH MAVEN

Create a simple Java project

Create a Java project from the Maven quick start template.

[pastacode lang=”javascript” manual=”%24%20mvn%20archetype%3Agenerate%20-DgroupId%3Dcom.wikitechy.core.utils%20-DartifactId%3DdateUtils%0A%20-DarchetypeArtifactId%3Dmaven-archetype-quickstart%20-DinteractiveMode%3Dfalse%0A” message=”javascript code” highlight=”” provider=”manual”/] [ad type=”banner”]

The following files and folder structure will be created.

[pastacode lang=”css” manual=”.%0A%7C____dateUtils%0A%7C%20%7C____pom.xml%0A%7C%20%7C____src%0A%7C%20%7C%20%7C____main%0A%7C%20%7C%20%7C%20%7C____java%0A%7C%20%7C%20%7C%20%7C%20%7C____com%0A%7C%20%7C%20%7C%20%7C%20%7C%20%7C____wikitechy%0A%7C%20%7C%20%7C%20%7C%20%7C%20%7C%20%7C____core%0A%7C%20%7C%20%7C%20%7C%20%7C%20%7C%20%7C%20%7C____utils%0A%7C%20%7C%20%7C%20%7C%20%7C%20%7C%20%7C%20%7C%20%7C____App.java%0A%7C%20%7C%20%7C____test%0A%7C%20%7C%20%7C%20%7C____java%0A%7C%20%7C%20%7C%20%7C%20%7C____com%0A%7C%20%7C%20%7C%20%7C%20%7C%20%7C____wikitechy%0A%7C%20%7C%20%7C%20%7C%20%7C%20%7C%20%7C____core%0A%7C%20%7C%20%7C%20%7C%20%7C%20%7C%20%7C%20%7C____utils%0A%7C%20%7C%20%7C%20%7C%20%7C%20%7C%20%7C%20%7C%20%7C____AppTest.java%0A” message=”css code” highlight=”” provider=”manual”/]

Above folder structure is not enough, create a log4j.properties file and put it in src/main/resources/log4j.properties, just create the resources folder manually.

log4j.properties

[pastacode lang=”java” manual=”%23%20Root%20logger%20option%0Alog4j.rootLogger%3DDEBUG%2C%20stdout%0A%0A%23%20Direct%20log%20messages%20to%20stdout%0Alog4j.appender.stdout%3Dorg.apache.log4j.ConsoleAppender%0Alog4j.appender.stdout.layout%3Dorg.apache.log4j.PatternLayout%0Alog4j.appender.stdout.layout.ConversionPattern%3D%25d%7BABSOLUTE%7D%20%255p%20%25c%7B1%7D%3A%25L%20-%20%25m%25n%0A” message=”java code” highlight=”” provider=”manual”/]

Make it support Eclipse.

[pastacode lang=”java” manual=”%24%20mvn%20eclipse%3Aeclipse%0A” message=”java code” highlight=”” provider=”manual”/] [ad type=”banner”]

Update Pom.xml

Update pom.xml to declare both log4j and the jodatime dependencies, for output to a jar format, make sure the packaging is set to “jar”.

pom.xml

Update App.java

App.java

[pastacode lang=”java” manual=”package%20com.wikitechy.core.utils%3B%0A%0Aimport%20org.apache.log4j.Logger%3B%0Aimport%20org.joda.time.LocalDate%3B%0A%0Apublic%20class%20App%20%0A%7B%0A%0A%09private%20static%20final%20Logger%20logger%20%3D%20Logger.getLogger(App.class)%3B%0A%0A%09public%20static%20void%20main(String%5B%5D%20args)%0A%20%7B%0A%09%09System.out.println(getLocalCurrentDate())%3B%0A%7D%0Aprivate%20static%20String%20getLocalCurrentDate()%20%7B%0A%0A%09%09if%20(logger.isDebugEnabled())%20%7B%0A%09%09%09logger.debug(%22getLocalCurrentDate()%20is%20executed!%22)%3B%0A%09%09%7D%0A%0A%09%09LocalDate%20date%20%3D%20new%20LocalDate()%3B%0A%09%09return%20date.toString()%3B%0A%0A%09%7D%0A%0A%7D%0A” message=”java code” highlight=”” provider=”manual”/]

Thus this project has two dependencies : log4j and jodatime.

Working with Dependencies

How to add dependencies in a jar

we can put both log4j.jar and jodatime.jar inside the final.jar, but our classes are unable to call other classes which is inside the unpack log4j.jar, Java jar is designed like this, unless we can create a special class loader like one-jar plugin.
Alternatively, use maven-assembly-plugin to extract all dependency jars into raw classes, and group it together.
Try one-jar plugin, it will create a fat-jar, which includes the entire project’s dependencies into a single jar file.

Solution

Copy the entire project’s dependencies to a pre-defined folder, and define the dependency class path in the jar’s manifest file.
The updated and final pom.xml, to use maven-dependency-plugin to copy all dependencies to target/dependency-jars/ folder, and use maven-jar-plugin to add the dependency class path.

pom.xml

[pastacode lang=”markup” manual=”%3Cproject%20xmlns%3D%22http%3A%2F%2Fmaven.apache.org%2FPOM%2F4.0.0%22%0A%09xmlns%3Axsi%3D%22http%3A%2F%2Fwww.w3.org%2F2001%2FXMLSchema-instance%22%0A%09xsi%3AschemaLocation%3D%22http%3A%2F%2Fmaven.apache.org%2FPOM%2F4.0.0%0A%09http%3A%2F%2Fmaven.apache.org%2Fmaven-v4_0_0.xsd%22%3E%0A%09%3CmodelVersion%3E4.0.0%3C%2FmodelVersion%3E%0A%09%3CgroupId%3Ecom.wikitechy.core.utils%3C%2FgroupId%3E%0A%09%3CartifactId%3EdateUtils%3C%2FartifactId%3E%0A%09%3Cpackaging%3Ejar%3C%2Fpackaging%3E%0A%09%3Cversion%3E1.0-SNAPSHOT%3C%2Fversion%3E%0A%09%3Cname%3EdateUtils%3C%2Fname%3E%0A%09%3Curl%3Ehttp%3A%2F%2Fmaven.apache.org%3C%2Furl%3E%0A%3Cproperties%3E%0A%09%09%3Cjdk.version%3E1.7%3C%2Fjdk.version%3E%0A%09%09%3Cjodatime.version%3E2.5%3C%2Fjodatime.version%3E%0A%09%09%3Cjunit.version%3E4.11%3C%2Fjunit.version%3E%0A%09%09%3Clog4j.version%3E1.2.17%3C%2Flog4j.version%3E%0A%09%09%3C%2Fproperties%3E%0A%3Cdependencies%3E%0A%09%09%3Cdependency%3E%0A%09%09%09%3CgroupId%3Ejunit%3C%2FgroupId%3E%0A%09%09%09%3CartifactId%3Ejunit%3C%2FartifactId%3E%0A%09%09%09%3Cversion%3E%24%7Bjunit.version%7D%3C%2Fversion%3E%0A%09%09%09%3Cscope%3Etest%3C%2Fscope%3E%0A%09%09%3C%2Fdependency%3E%0A%09%09%3Cdependency%3E%0A%09%09%09%3CgroupId%3Ejoda-time%3C%2FgroupId%3E%0A%09%09%09%3CartifactId%3Ejoda-time%3C%2FartifactId%3E%0A%09%09%09%3Cversion%3E%24%7Bjodatime.version%7D%3C%2Fversion%3E%0A%09%09%3C%2Fdependency%3E%0A%3Cdependency%3E%0A%09%09%09%3CgroupId%3Elog4j%3C%2FgroupId%3E%0A%09%09%09%3CartifactId%3Elog4j%3C%2FartifactId%3E%0A%09%09%09%3Cversion%3E%24%7Blog4j.version%7D%3C%2Fversion%3E%0A%09%09%3C%2Fdependency%3E%0A%09%3C%2Fdependencies%3E%0A%0A%09%3Cbuild%3E%0A%09%09%3CfinalName%3Edateutils%3C%2FfinalName%3E%0A%09%09%3Cplugins%3E%0A%0A%09%09%09%3C!–%20download%20source%20code%20in%20Eclipse%2C%20best%20practice%20–%3E%0A%09%09%09%3Cplugin%3E%0A%09%09%09%09%3CgroupId%3Eorg.apache.maven.plugins%3C%2FgroupId%3E%0A%09%09%09%09%3CartifactId%3Emaven-eclipse-plugin%3C%2FartifactId%3E%0A%09%09%09%09%3Cversion%3E2.9%3C%2Fversion%3E%0A%09%09%09%09%3Cconfiguration%3E%0A%09%09%09%09%09%3CdownloadSources%3Etrue%3C%2FdownloadSources%3E%0A%09%09%09%09%09%3CdownloadJavadocs%3Efalse%3C%2FdownloadJavadocs%3E%0A%09%09%09%09%3C%2Fconfiguration%3E%0A%09%09%09%3C%2Fplugin%3E%0A%3Cdependency%3E%0A%09%09%09%3CgroupId%3Elog4j%3C%2FgroupId%3E%0A%09%09%09%3CartifactId%3Elog4j%3C%2FartifactId%3E%0A%09%09%09%3Cversion%3E%24%7Blog4j.version%7D%3C%2Fversion%3E%0A%09%09%3C%2Fdependency%3E%0A%09%3C%2Fdependencies%3E%0A%0A%09%3Cbuild%3E%0A%09%09%3CfinalName%3Edateutils%3C%2FfinalName%3E%0A%09%09%3Cplugins%3E%0A%0A%09%09%09%3C!–%20download%20source%20code%20in%20Eclipse%2C%20best%20practice%20–%3E%0A%09%09%09%3Cplugin%3E%0A%09%09%09%09%3CgroupId%3Eorg.apache.maven.plugins%3C%2FgroupId%3E%0A%09%09%09%09%3CartifactId%3Emaven-eclipse-plugin%3C%2FartifactId%3E%0A%09%09%09%09%3Cversion%3E2.9%3C%2Fversion%3E%0A%09%09%09%09%3Cconfiguration%3E%0A%09%09%09%09%09%3CdownloadSources%3Etrue%3C%2FdownloadSources%3E%0A%09%09%09%09%09%3CdownloadJavadocs%3Efalse%3C%2FdownloadJavadocs%3E%0A%09%09%09%09%3C%2Fconfiguration%3E%0A%09%09%09%3C%2Fplugin%3E%0A%3C!–%20Set%20a%20compiler%20level%20–%3E%0A%09%09%09%3Cplugin%3E%0A%09%09%09%09%3CgroupId%3Eorg.apache.maven.plugins%3C%2FgroupId%3E%0A%09%09%09%09%3CartifactId%3Emaven-compiler-plugin%3C%2FartifactId%3E%0A%09%09%09%09%3Cversion%3E2.3.2%3C%2Fversion%3E%0A%09%09%09%09%3Cconfiguration%3E%0A%09%09%09%09%09%3Csource%3E%24%7Bjdk.version%7D%3C%2Fsource%3E%0A%09%09%09%09%09%3Ctarget%3E%24%7Bjdk.version%7D%3C%2Ftarget%3E%0A%09%09%09%09%3C%2Fconfiguration%3E%0A%09%09%09%3C%2Fplugin%3E%0A%3C!–%20Make%20this%20jar%20executable%20–%3E%0A%09%09%09%3Cplugin%3E%0A%09%09%09%09%3CgroupId%3Eorg.apache.maven.plugins%3C%2FgroupId%3E%0A%09%09%09%09%3CartifactId%3Emaven-jar-plugin%3C%2FartifactId%3E%0A%09%09%09%09%3Cconfiguration%3E%0A%09%09%09%09%20%20%3Cexcludes%3E%0A%09%09%09%09%09%3Cexclude%3E**%2Flog4j.properties%3C%2Fexclude%3E%0A%09%09%09%09%20%20%3C%2Fexcludes%3E%0A%3Carchive%3E%0A%3Cmanifest%3E%0A%3CaddClasspath%3Etrue%3C%2FaddClasspath%3E%0A%3CmainClass%3Ecom.wikitechy.core.utils.App%3C%2FmainClass%3E%0A%3CclasspathPrefix%3Edependency-jars%2F%3C%2FclasspathPrefix%3E%0A%3C%2Fmanifest%3E%0A%3C%2Farchive%3E%0A%3C%2Fconfiguration%3E%0A%3C%2Fplugin%3E%0A%0A%3C!–%20Copy%20project%20dependency%20–%3E%0A%09%09%09%3Cplugin%3E%0A%09%09%09%09%3CgroupId%3Eorg.apache.maven.plugins%3C%2FgroupId%3E%0A%09%09%09%09%3CartifactId%3Emaven-dependency-plugin%3C%2FartifactId%3E%0A%09%09%09%09%3Cversion%3E2.5.1%3C%2Fversion%3E%0A%09%09%09%09%3Cexecutions%3E%0A%09%09%09%09%20%3Cexecution%3E%0A%3Cid%3Ecopy-dependencies%3C%2Fid%3E%0A%09%09%09%09%09%3Cphase%3Epackage%3C%2Fphase%3E%0A%09%09%09%09%09%3Cgoals%3E%0A%09%09%09%09%09%09%3Cgoal%3Ecopy-dependencies%3C%2Fgoal%3E%0A%09%09%09%09%09%3C%2Fgoals%3E%0A%09%09%09%09%09%3Cconfiguration%3E%0A%20%3C!–%20exclude%20junit%2C%20we%20need%20runtime%20dependency%20only%20–%3E%0A%09%09%09%3CincludeScope%3Eruntime%3C%2FincludeScope%3E%0A%09%09%09%3CoutputDirectory%3E%24%7Bproject.build.directory%7D%2Fdependency-jars%2F%3C%2FoutputDirectory%3E%0A%09%09%09%09%09%3C%2Fconfiguration%3E%0A%09%09%09%09%20%20%3C%2Fexecution%3E%0A%09%09%09%09%3C%2Fexecutions%3E%0A%09%09%09%3C%2Fplugin%3E%0A%0A%09%09%3C%2Fplugins%3E%0A%09%3C%2Fbuild%3E%0A%0A%3C%2Fproject%3E%0A” message=”html code” highlight=”” provider=”manual”/] [ad type=”banner”]

final Jar file

Package

[pastacode lang=”javascript” manual=”%24%20mvn%20package%0A” message=”javascript code” highlight=”” provider=”manual”/]

Review the folder structure in the target folder

A dateutils.jar is created, and the entire project runtime dependencies (excluded junit) are copied to target/dependency-jars/ folder.

List out the dateutils.jar content :

[pastacode lang=”javascript” manual=”%24%20jar%20tf%20target%2Fdateutils.jar%0AMETA-INF%2F%0AMETA-INF%2FMANIFEST.MF%0Acom%2F%0Acom%2Fwikitechy%2F%0Acom%2Fwikitechy%2Fcore%2F%0Acom%2Fwikitechy%2Fcore%2Futils%2F%0Acom%2Fwikitechy%2Fcore%2Futils%2FApp.class%0AMETA-INF%2Fmaven%2F%0AMETA-INF%2Fmaven%2Fcom.wikitechy.core.utils%2F%0AMETA-INF%2Fmaven%2Fcom.wikitechy.core.utils%2FdateUtils%2F%0AMETA-INF%2Fmaven%2Fcom.wikitechy.core.utils%2FdateUtils%2Fpom.xml%0AMETA-INF%2Fmaven%2Fcom.wikitechy.core.utils%2FdateUtils%2Fpom.properties%0A%0A” message=”javascript code” highlight=”” provider=”manual”/]

Extracts and review the content of MANIFEST.MF, the dependencies are added in the Class-Path.

[pastacode lang=”javascript” manual=”META_INF%2FMANIFEST.MF%0AManifest-Version%3A%201.0%0ABuilt-By%3A%20wikitechy%0ABuild-Jdk%3A%201.7.0_05%0AClass-Path%3A%20dependency-jars%2Fjoda-time-2.5.jar%20dependency-jars%2Flog4j-1.2.17.jar%0ACreated-By%3A%20Apache%20Maven%203.1.1%0AMain-Class%3A%20com.wikitechy.core.utils.App%0AArchiver-Version%3A%20Plexus%20Archiver%0A” message=”javascript code” highlight=”” provider=”manual”/] [ad type=”banner”]

Run it

[pastacode lang=”javascript” manual=”%24%20java%20-jar%20target%2Fdateutils.jar%0A%0Alog4j%3AWARN%20No%20appenders%20could%20be%20found%20for%20logger%20(com.wikitechy.core.utils.App).%0Alog4j%3AWARN%20Please%20initialize%20the%20log4j%20system%20properly.%0Alog4j%3AWARN%20See%20http%3A%2F%2Flogging.apache.org%2Flog4j%2F1.2%2Ffaq.html%23noconfig%20for%20more%20info.%0A2014-10-19%0A” message=”javascript code” highlight=”” provider=”manual”/]

Where is log4j.properties?

To exclude the log4j.properties in the jar file, to avoid issues like multiple log4j.properties files in classpath.

We can still pass in the log4j properties via the log4j.configuration system property like this :

[pastacode lang=”javascript” manual=”%24%20java%20-jar%20-Dlog4j.configuration%3Dfile%3A%2Ffull_path%2Flog4j.properties%20target%2Fdateutils.jar%0A%0A17%3A09%3A15%2C385%20DEBUG%20App%3A18%20-%20getLocalCurrentDate()%20is%20executed!%0A” message=”javascript code” highlight=”” provider=”manual”/]

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JAVA – How to create an executable JAR with dependencies using Maven

Maven

A JAR (Java ARchive)

TO CREATE A JAR FILE WITH MAVEN

log4j.properties

Make it support Eclipse.

Update Pom.xml

pom.xml

Update App.java

App.java

Working with Dependencies

How to add dependencies in a jar

Solution

pom.xml

final Jar file

Package

List out the dateutils.jar content :

Run it

Where is log4j.properties?

Wikitechy Editor

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Maven

A JAR (Java ARchive)

TO CREATE A JAR FILE WITH MAVEN

log4j.properties

Make it support Eclipse.

Update Pom.xml

pom.xml

Update App.java

App.java

Working with Dependencies

How to add dependencies in a jar

Solution

pom.xml

final Jar file

Package

List out the dateutils.jar content :

Run it

Where is log4j.properties?

Leave a Reply

Related Articles

Other Stories

[Solved -11 Answers] HTML – Word-wrap in an HTML table

[ Solved – 12 Answers ] JAVASCRIPT – How to check for an empty string in JavaScript