Classpath including JAR within a JAR

Question

Is it possible to specify a Java classpath that includes a JAR file contained within another JAR file

User · Answer

I use maven for my java builds which has a plugin called the maven assembly plugin.

It does what your asking, but like some of the other suggestions describe - essentially exploding all the dependent jars and recombining them into a single jar

User · Answer

Use the zipgroupfileset tag  uses same attributes as a fileset tag   it will unzip all files in the directory and add to your new archive file  More information  http   ant apache org manual Tasks zip html  This is a very useful way to get around the jar-in-a-jar problem -- I know because I have googled this exact StackOverflow question while trying to figure out what to do  If you want to package a jar or a folder of jars into your one built jar with Ant  then forget about all this classpath or third-party plugin stuff  all you gotta do is this  in Ant     lt jar destfile  your jar  basedir  java dir  gt           lt zipgroupfileset dir  dir of jars    gt   lt  jar gt

User · Answer

After some research I have found method that doesn t require maven or any 3rd party extension program    You can use  Class-Path  in your manifest file   For example   Create manifest file MANIFEST MF  Manifest-Version  1 0 Created-By  Bundle Class-Path    custom lib jar Main-Class  YourMainClass   Compile all your classes and run jar cfm Testing jar MANIFEST MF   class custom lib jar  c stands for create archive f indicates that you want to specify file  v is for verbose input m means that we will pass custom manifest file  Be sure that you included lib in jar package  You should be able to run jar in the normal way   based on  http   www ibm com developerworks library j-5things6   all other information you need about the class-path do you find here

User · Answer

Well  there is a very easy way if you re using Eclipse    Export your project as a  Runnable  Jar file  right-click project folder from within Eclipse  select  Export       When you configure the export settings  be sure to select  Extract required libraries into generated Jar   Keep in mind  select  Extract     and not  Package required libraries        Additionally  You must select a run-configuration in your export settings  So  you could always create an empty main    in some class and use it for your run configuration    Anyway  it isn t guaranteed to work 100  of the time - as you will notice a pop-up message telling you to make sure you check the licenses of the Jar files you re including and something about not copying signature files  However  I have been doing this for years and have never encountered a problem

User · Answer

If you re trying to create a single jar that contains your application and its required libraries  there are two ways  that I know of  to do that   The first is One-Jar  which uses a special classloader to allow the nesting of jars   The second is UberJar   or Shade   which explodes the included libraries and puts all the classes in the top-level jar   I should also mention that UberJar and Shade are plugins for Maven1 and Maven2 respectively   As mentioned below  you can also use the assembly plugin  which in reality is much more powerful  but much harder to properly configure

User · Answer

I was about to advise to extract all the files at the same level  then to make a jar out of the result  since the package system should keep them neatly separated  That would be the manual way  I suppose the tools indicated by Steve will do that nicely

User · Answer

I use maven for my java builds which has a plugin called the maven assembly plugin.

It does what your asking, but like some of the other suggestions describe - essentially exploding all the dependent jars and recombining them into a single jar

User · Answer

I use maven for my java builds which has a plugin called the maven assembly plugin.

It does what your asking, but like some of the other suggestions describe - essentially exploding all the dependent jars and recombining them into a single jar

User · Answer

Not without writing your own class loader   You can add jars to the jar s classpath  but they must be co-located  not contained in the main jar

User · Answer

You do NOT want to use those  explode JAR contents  solutions   They definitely make it harder to see stuff  since everything is exploded at the same level    Furthermore  there could be naming conflicts  should not happen if people use proper packages  but you cannot always control this    The feature that you want is one of the top 25 Sun RFEs  RFE 4648386  which Sun  in their infinite wisdom  has designated as being of low priority  We can only hope that Sun wakes up     In the meanwhile  the best solution that I have come across  which I wish that Sun would copy in the JDK  is to use the custom class loader JarClassLoader

User · Answer

Not without writing your own class loader   You can add jars to the jar s classpath  but they must be co-located  not contained in the main jar

User · Answer

Winstone is pretty good http   blog jayway com 2008 11 28 executable-war-with-winstone-maven-plugin   But not for complex sites  And that s a shame because all it takes is to include the plugin

User · Answer

Winstone is pretty good http   blog jayway com 2008 11 28 executable-war-with-winstone-maven-plugin   But not for complex sites  And that s a shame because all it takes is to include the plugin

User · Answer

If you re trying to create a single jar that contains your application and its required libraries  there are two ways  that I know of  to do that   The first is One-Jar  which uses a special classloader to allow the nesting of jars   The second is UberJar   or Shade   which explodes the included libraries and puts all the classes in the top-level jar   I should also mention that UberJar and Shade are plugins for Maven1 and Maven2 respectively   As mentioned below  you can also use the assembly plugin  which in reality is much more powerful  but much harder to properly configure

User · Answer

I was about to advise to extract all the files at the same level  then to make a jar out of the result  since the package system should keep them neatly separated  That would be the manual way  I suppose the tools indicated by Steve will do that nicely

User · Answer

After some research I have found method that doesn t require maven or any 3rd party extension program    You can use  Class-Path  in your manifest file   For example   Create manifest file MANIFEST MF  Manifest-Version  1 0 Created-By  Bundle Class-Path    custom lib jar Main-Class  YourMainClass   Compile all your classes and run jar cfm Testing jar MANIFEST MF   class custom lib jar  c stands for create archive f indicates that you want to specify file  v is for verbose input m means that we will pass custom manifest file  Be sure that you included lib in jar package  You should be able to run jar in the normal way   based on  http   www ibm com developerworks library j-5things6   all other information you need about the class-path do you find here

User · Answer

If you have eclpise IDE  you just need to export your JAR and choose  Package Required libraries into generated JAR   eclipse will automatically add the required dependant JARs into the generated JAR as well as generated some eclipse custom class loader that load these JARs automatically

User · Answer

You need to build a custom class-loader to do this or a third-party library that supports this  Your best bet is to extract the jar from the runtime and add them to the classpath  or have them already added to the classpath

User · Answer

Extracting into an Uber-dir works for me as we s should all be using root  java and have outlets code in packages with versioning  Ie ca tecreations-1 0 0  Signing is okay because the jars are intact from their downloaded location  3rd party signatures intact  extract to c  java  There   s my project dir  run from launcher so java -cp c  java Launcher

User · Answer

If you have eclpise IDE  you just need to export your JAR and choose  Package Required libraries into generated JAR   eclipse will automatically add the required dependant JARs into the generated JAR as well as generated some eclipse custom class loader that load these JARs automatically

User · Answer

Use the zipgroupfileset tag  uses same attributes as a fileset tag   it will unzip all files in the directory and add to your new archive file  More information  http   ant apache org manual Tasks zip html  This is a very useful way to get around the jar-in-a-jar problem -- I know because I have googled this exact StackOverflow question while trying to figure out what to do  If you want to package a jar or a folder of jars into your one built jar with Ant  then forget about all this classpath or third-party plugin stuff  all you gotta do is this  in Ant     lt jar destfile  your jar  basedir  java dir  gt           lt zipgroupfileset dir  dir of jars    gt   lt  jar gt

User · Answer

I use maven for my java builds which has a plugin called the maven assembly plugin.

It does what your asking, but like some of the other suggestions describe - essentially exploding all the dependent jars and recombining them into a single jar

User · Answer

You need to build a custom class-loader to do this or a third-party library that supports this  Your best bet is to extract the jar from the runtime and add them to the classpath  or have them already added to the classpath

User · Answer

If you are building with ant  I am using ant from eclipse   you can just add the extra jar files by saying to ant to add them    Not necessarily the best method if you have a project maintained by multiple people but it works for one person project and is easy   for example my target that was building the  jar file was    lt jar destfile    plugin jar   basedir    plugin build dir   gt       lt manifest gt           lt attribute name  Author  value  ntg   gt                                                    lt attribute name  Plugin-Version  value    version entry commit revision    gt       lt  manifest gt   lt  jar gt    I just added one line to make it    lt jar       gt       lt zipgroupfileset dir    external-lib-dir   includes    jar   gt       lt manifest gt                                                lt  manifest gt   lt  jar gt    where   lt property name  external-lib-dir             value  C      eclipseWorkspace Filter external     lib    gt    was the dir with the external jars  And that s it

User · Answer

If you re trying to create a single jar that contains your application and its required libraries  there are two ways  that I know of  to do that   The first is One-Jar  which uses a special classloader to allow the nesting of jars   The second is UberJar   or Shade   which explodes the included libraries and puts all the classes in the top-level jar   I should also mention that UberJar and Shade are plugins for Maven1 and Maven2 respectively   As mentioned below  you can also use the assembly plugin  which in reality is much more powerful  but much harder to properly configure

User · Answer

If you are building with ant  I am using ant from eclipse   you can just add the extra jar files by saying to ant to add them    Not necessarily the best method if you have a project maintained by multiple people but it works for one person project and is easy   for example my target that was building the  jar file was    lt jar destfile    plugin jar   basedir    plugin build dir   gt       lt manifest gt           lt attribute name  Author  value  ntg   gt                                                    lt attribute name  Plugin-Version  value    version entry commit revision    gt       lt  manifest gt   lt  jar gt    I just added one line to make it    lt jar       gt       lt zipgroupfileset dir    external-lib-dir   includes    jar   gt       lt manifest gt                                                lt  manifest gt   lt  jar gt    where   lt property name  external-lib-dir             value  C      eclipseWorkspace Filter external     lib    gt    was the dir with the external jars  And that s it

User · Answer

I was about to advise to extract all the files at the same level  then to make a jar out of the result  since the package system should keep them neatly separated  That would be the manual way  I suppose the tools indicated by Steve will do that nicely

User · Answer

Extracting into an Uber-dir works for me as we s should all be using root  java and have outlets code in packages with versioning  Ie ca tecreations-1 0 0  Signing is okay because the jars are intact from their downloaded location  3rd party signatures intact  extract to c  java  There   s my project dir  run from launcher so java -cp c  java Launcher

User · Answer

Well  there is a very easy way if you re using Eclipse    Export your project as a  Runnable  Jar file  right-click project folder from within Eclipse  select  Export       When you configure the export settings  be sure to select  Extract required libraries into generated Jar   Keep in mind  select  Extract     and not  Package required libraries        Additionally  You must select a run-configuration in your export settings  So  you could always create an empty main    in some class and use it for your run configuration    Anyway  it isn t guaranteed to work 100  of the time - as you will notice a pop-up message telling you to make sure you check the licenses of the Jar files you re including and something about not copying signature files  However  I have been doing this for years and have never encountered a problem

User · Answer

You need to build a custom class-loader to do this or a third-party library that supports this  Your best bet is to extract the jar from the runtime and add them to the classpath  or have them already added to the classpath

User · Answer

You do NOT want to use those  explode JAR contents  solutions   They definitely make it harder to see stuff  since everything is exploded at the same level    Furthermore  there could be naming conflicts  should not happen if people use proper packages  but you cannot always control this    The feature that you want is one of the top 25 Sun RFEs  RFE 4648386  which Sun  in their infinite wisdom  has designated as being of low priority  We can only hope that Sun wakes up     In the meanwhile  the best solution that I have come across  which I wish that Sun would copy in the JDK  is to use the custom class loader JarClassLoader

User · Answer

Not without writing your own class loader   You can add jars to the jar s classpath  but they must be co-located  not contained in the main jar

User · Answer

If you re trying to create a single jar that contains your application and its required libraries  there are two ways  that I know of  to do that   The first is One-Jar  which uses a special classloader to allow the nesting of jars   The second is UberJar   or Shade   which explodes the included libraries and puts all the classes in the top-level jar   I should also mention that UberJar and Shade are plugins for Maven1 and Maven2 respectively   As mentioned below  you can also use the assembly plugin  which in reality is much more powerful  but much harder to properly configure

User · Answer

You need to build a custom class-loader to do this or a third-party library that supports this  Your best bet is to extract the jar from the runtime and add them to the classpath  or have them already added to the classpath

User · Answer

Not without writing your own class loader   You can add jars to the jar s classpath  but they must be co-located  not contained in the main jar

User · Answer

I was about to advise to extract all the files at the same level  then to make a jar out of the result  since the package system should keep them neatly separated  That would be the manual way  I suppose the tools indicated by Steve will do that nicely

[java] Classpath including JAR within a JAR

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