How do I put all required JAR files in a library folder inside the final JAR file with Maven

Question

I am using Maven in my standalone application  and I want to package all the dependencies in my JAR file inside a library folder  as mentioned in one of the answers here   How can I create an executable JAR with dependencies using Maven   I want my final JAR file to have a library folder that contains the dependencies as JAR files  not like what the maven-shade-plugin that puts the dependencies in the form of folders like the Maven hierarchy in the  m2 folder   Well  actually the current configuration does what I want  but I am having a problem with loading the JAR files when running the application  I can t load the classes   Here s my configuration    lt plugins gt        lt plugin gt           lt groupId gt org apache maven plugins lt  groupId gt           lt artifactId gt maven-dependency-plugin lt  artifactId gt           lt executions gt               lt execution gt                   lt id gt copy-dependencies lt  id gt                   lt phase gt prepare-package lt  phase gt                   lt goals gt                       lt goal gt copy-dependencies lt  goal gt                   lt  goals gt                   lt configuration gt                       lt outputDirectory gt   project build directory  classes lib lt  outputDirectory gt                       lt overWriteReleases gt false lt  overWriteReleases gt                       lt overWriteSnapshots gt false lt  overWriteSnapshots gt                       lt overWriteIfNewer gt true lt  overWriteIfNewer gt                   lt  configuration gt               lt  execution gt           lt  executions gt       lt  plugin gt        lt plugin gt           lt groupId gt org apache maven plugins lt  groupId gt           lt artifactId gt maven-jar-plugin lt  artifactId gt           lt configuration gt               lt archive gt                   lt manifest gt                       lt addClasspath gt true lt  addClasspath gt                       lt classpathPrefix gt lib  lt  classpathPrefix gt                       lt mainClass gt com myapp MainClass lt  mainClass gt                   lt  manifest gt               lt  archive gt           lt  configuration gt       lt  plugin gt        lt plugin gt           lt groupId gt org apache maven plugins lt  groupId gt           lt artifactId gt maven-compiler-plugin lt  artifactId gt           lt configuration gt               lt source gt 1 6 lt  source gt               lt target gt 1 6 lt  target gt           lt  configuration gt       lt  plugin gt        lt plugin gt           lt groupId gt org apache maven plugins lt  groupId gt           lt artifactId gt maven-dependency-plugin lt  artifactId gt           lt executions gt               lt execution gt                   lt id gt install lt  id gt                   lt phase gt install lt  phase gt                   lt goals gt                       lt goal gt sources lt  goal gt                   lt  goals gt               lt  execution gt           lt  executions gt       lt  plugin gt        lt plugin gt           lt groupId gt org apache maven plugins lt  groupId gt           lt artifactId gt maven-resources-plugin lt  artifactId gt           lt version gt 2 5 lt  version gt           lt configuration gt               lt encoding gt UTF-8 lt  encoding gt           lt  configuration gt       lt  plugin gt    lt  plugins gt    The project runs fine from Eclipse  and the JAR files are put in the library folder inside my final JAR file as I want  but when running the final JAR file from the target folder I always get ClassNotFoundException   Exception in thread  main  java lang NoClassDefFoundError  org springframework context ApplicationContext Caused by  java lang ClassNotFoundException  org springframework context ApplicationContext         at java net URLClassLoader 1 run Unknown Source          at java security AccessController doPrivileged Native Method          at java net URLClassLoader findClass Unknown Source          at java lang ClassLoader loadClass Unknown Source          at sun misc Launcher AppClassLoader loadClass Unknown Source          at java lang ClassLoader loadClass Unknown Source  Could not find the main class  com myapp MainClass  Program will exit    How can I fix this exception

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Updated    lt build gt      lt plugins gt        lt plugin gt        lt artifactId gt maven-dependency-plugin lt  artifactId gt        lt executions gt          lt execution gt            lt phase gt install lt  phase gt              lt goals gt                lt goal gt copy-dependencies lt  goal gt              lt  goals gt              lt configuration gt                 lt outputDirectory gt   project build directory  lib lt  outputDirectory gt              lt  configuration gt            lt  execution gt          lt  executions gt        lt  plugin gt      lt  plugins gt    lt  build gt

User · Answer

following this link   How To  Eclipse Maven install build jar with dependencies  i found out that this is not workable solution because the class loader doesn t load jars from within jars  so i think that i will unpack the dependencies inside the jar

User · Answer

The executable packer maven plugin can be used for exactly that purpose  creating standalone java applications containing all dependencies as JAR files in a specific folder   Just add the following to your pom xml inside the  lt build gt  lt plugins gt  section  be sure to replace the value of mainClass accordingly     lt plugin gt       lt groupId gt de ntcomputer lt  groupId gt       lt artifactId gt executable-packer-maven-plugin lt  artifactId gt       lt version gt 1 0 1 lt  version gt       lt configuration gt           lt mainClass gt com example MyMainClass lt  mainClass gt       lt  configuration gt       lt executions gt           lt execution gt               lt goals gt                   lt goal gt pack-executable-jar lt  goal gt               lt  goals gt           lt  execution gt       lt  executions gt   lt  plugin gt    The built JAR file is located at target  lt YourProjectAndVersion gt -pkg jar after you run mvn package  All of its compile-time and runtime dependencies will be included in the lib  folder inside the JAR file   Disclaimer  I am the author of the plugin

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This is clearly a classpath problem  Take into consideration that the classpath must change a bit when you run your program outside the IDE  This is because the IDE loads the other JARs relative to the root folder of your project  while in the case of the final JAR this is usually not true   What I like to do in these situations is build the JAR manually  It takes me at most 5 minutes and it always solves the problem  I do not suggest you do this  Find a way to use Maven  that s its purpose

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The following is my solution  Test it if it works for you    lt plugin gt       lt groupId gt org apache maven plugins lt  groupId gt       lt artifactId gt maven-dependency-plugin lt  artifactId gt       lt executions gt           lt execution gt               lt id gt copy-dependencies lt  id gt               lt phase gt prepare-package lt  phase gt               lt goals gt                   lt goal gt copy-dependencies lt  goal gt               lt  goals gt               lt configuration gt                   lt outputDirectory gt   project build directory  classes lib lt  outputDirectory gt                   lt overWriteReleases gt false lt  overWriteReleases gt                   lt overWriteSnapshots gt false lt  overWriteSnapshots gt                   lt overWriteIfNewer gt true lt  overWriteIfNewer gt               lt  configuration gt           lt  execution gt       lt  executions gt   lt  plugin gt    lt plugin gt       lt groupId gt org apache maven plugins lt  groupId gt       lt artifactId gt maven-jar-plugin lt  artifactId gt       lt configuration gt           lt archive gt               lt manifest gt                   lt addClasspath gt true lt  addClasspath gt                   lt  --  lt classpathPrefix gt lib lt  classpathPrefix gt  -- gt                   lt  --  lt mainClass gt test org Cliente lt  mainClass gt  -- gt               lt  manifest gt               lt manifestEntries gt                   lt Class-Path gt lib  lt  Class-Path gt               lt  manifestEntries gt           lt  archive gt       lt  configuration gt   lt  plugin gt    The first plugin puts all dependencies in the target classes lib folder  and the second one includes the library folder in the final JAR file  and configures the Manifest mf file   But then you will need to add custom classloading code to load the JAR files   Or  to avoid custom classloading  you can use    project build directory  lib  but in this case  you don t have dependencies inside the final JAR file  which defeats the purpose   It s been two years since the question was asked  The problem of nested JAR files persists nevertheless  I hope it helps somebody

User · Answer

Here  s how I do it        lt plugin gt               lt artifactId gt maven-assembly-plugin lt  artifactId gt               lt version gt 2 2 lt  version gt               lt configuration gt                   lt appendAssemblyId gt false lt  appendAssemblyId gt                   lt descriptorRefs gt                       lt descriptorRef gt jar-with-dependencies lt  descriptorRef gt                   lt  descriptorRefs gt                   lt archive gt                       lt manifest gt                           lt mainClass gt com project MainClass lt  mainClass gt                       lt  manifest gt                   lt  archive gt               lt  configuration gt           lt  plugin gt    And then I just run   mvn assembly assembly

User · Answer

The simplest and the most efficient way is to use an uber plugin like this             lt plugin gt               lt groupId gt org apache maven plugins lt  groupId gt               lt artifactId gt maven-shade-plugin lt  artifactId gt               lt executions gt                   lt execution gt                       lt phase gt package lt  phase gt                       lt goals gt                           lt goal gt shade lt  goal gt                       lt  goals gt                   lt  execution gt               lt  executions gt               lt configuration gt                   lt finalName gt uber-  project artifactId -  project version  lt  finalName gt               lt  configuration gt           lt  plugin gt   You will have de-normalized all in one JAR file

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I found this answer to the question   http   padcom13 blogspot co uk 2011 10 creating-standalone-applications-with html  Not only do you get the dependent lib files in a lib folder  you also get a bin director with both a unix and a dos executable   The executable ultimately calls java with a -cp argument that lists all of your dependent libs too   The whole lot sits in an appasembly folder inside the target folder  Epic                 Yes I know this is an old thread  but it s still coming high on search results so I thought it might help someone like me

[java] How do I put all required JAR files in a library folder inside the final JAR file with Maven?

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