Corrupt jar file

Question

I have created a jar file in windows 7 using eclipse  When I am trying to open the jar file it says invalid or corrupt jar file  Can anyone suggest me why the jar file is invalid

User · Answer

If the jar file has any extra bytes at the end, explorers like 7-Zip can open it, but it will be treated as corrupt. I use an online upload system that automatically adds a single extra LF character ('\n', 0x0a) to the end of every jar file. With such files, there are a variety solutions to run the file:

Use prayagubd's approach and specify the .jar as the classpath and name of the main class at the command prompt
Remove the extra byte at the end of the file (with a hex-editor or a command like head -c -1 myjar.jar), and then execute the jar by double-clicking or with java -jar myfile.jar as normal.
Change the extension from .jar to .zip, extract the files, and recreate the .zip file, being sure that the META-INF folder is in the top-level.
Changing the .jar extension to .zip, deleting an uneeded file from within the .jar, and change the extension back to .jar

All of these solutions require that the structure of the .zip and the META-INF file is essentially correct. They have only been tested with a single extra byte at the end of the zip "corrupting" it.

I got myself in a real mess by applying head -c -1 *.jar > tmp.jar twice. head inserted the ASCII text ==> myjar.jar <== at the start of the file, completely corrupting it.

User · Answer

This regularly occurs when you change the extension on the JAR for ZIP  extract the zip content and make some modifications on files such as changing the MANIFEST MF file which is a very common case  many times Eclipse doesn t generate the MANIFEST file as we want  or maybe we would like to modify the CLASS-PATH or the MAIN-CLASS values of it    The problem occurs when you zip back the folder   A valid Runnable Executable JAR has the next structure   myJAR  Main-Directory       -META-INF  Mandatory                -MANIFEST MF  Mandatory Main-class  com MainClass       -com            -MainClass class  must to implement the main method  mandatory       -properties files  optional       -etc  optional    If your JAR complies with these rules it will work doesn t matter if you build it manually by using a ZIP tool and then you changed the extension back to  jar  Once you re done try execute it on the command line using   java -jar myJAR jar    When you use a zip tool to unpack  change files and zip again  normally the JAR structure changes to this structure which is incorrect  since another directory level is added on the top of the file system making it a corrupted file as is shown below     myJAR  Main-Directory       -myJAR  creates another directory making the file corrupted               -META-INF  Mandatory                      -MANIFEST MF  Mandatory Main-class  com MainClass             -com                 -MainClass class  must to implement the main method  mandatory             -properties files  optional             -etc  optional

User · Answer

Maybe this was just a fluke but the one time I had this error  I simply had to kill all javaw exe processes that were running in the background  The executable JAR worked after that

User · Answer

It can be a typo int the MANIFEST MF too  p ex  Build-Date with two      Build-Date   2017-03-13 16 07 12

User · Answer

It can be something so silly as you are transferring the file via FTP to a target machine  you go and run the  JAR file but this was so big that it has not yet been finished transferred    Yes it happened to me

User · Answer

As I just came across this topic I wanted to share the reason and solution why I got the message  invalid or corrupt jarfile    I had updated the version of the  maven-jar-plugin  in my pom xml from 2 1 to 3 1 2  Everything still went fine and a jar file was built  But somehow it obviously wouldn t run anymore   As soon as i set the  maven-jar-plugin  version back to 2 1 again  the problem was gone

User · Answer

This will happen when you doubleclick a JAR file in Windows explorer  but the JAR is by itself actually not an executable JAR  A real executable JAR should have at least a class with a main   method and have it referenced in MANIFEST MF   In Eclispe  you need to export the project as Runnable JAR file instead of as JAR file to get a real executable JAR   Or  if your JAR is solely a container of a bunch of closely related classes  a library   then you shouldn t doubleclick it  but open it using some ZIP tool  Windows explorer namely by default associates JAR files with java exe  which won t work for those kind of libary JARs

User · Answer

Also  make sure that the java version used at runtime is an equivalent or later version than the java used during compilation

User · Answer

Could be because of issue with MANIFEST MF  Try starting main class with following command if you know the package where main class is located   java -cp launcher target usergrid-launcher-1 0-SNAPSHOT jar co pseudononymous Server

User · Answer

This is the common issue with  manifest  in the error  Yes it happens a lot  here s a link  http   dev-answers blogspot com 2006 07 invalid-or-corrupt-jarfile html     Solution       Using the ant task to create the manifest file on-the-fly gives you and entry like   Manifest-Version  1 0 Ant-Version  Apache Ant 1 6 2 Created-By  1 4 2 07-b05  Sun Microsystems Inc   Main-Class  com example MyMainClass       Creating the manifest file myself  with the bare essentials fixes the issue   Manifest-Version  1 0 Main-Class  com example MyMainClass       With more investigation I m sure I could have got the dynamic meta-file creation working with Ant as I know other people do - there must be some peculiarity in the combination of my ant version  1 6 2   java version  1 4 2 07  and perhaps the current phase of the moon       Notes       Parsing of the Meta-inf file has been an issue that has come-up  been fixed and then come-up again for sun  See  Bug Id  4991229  If you can work out if this bug exists in the your  or my  version of the Java SE you have more patience that me

User · Answer

The problem might be that there are more than 65536 files in your JAR  Why java complains about jar files with lots of entries  The fix is described in this question s answer

User · Answer

Try use the command jar -xvf fileName jar and then do export the content of the decompressed file into a new Java project into Eclipse

[java] Corrupt jar file

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