how to open a jar file in Eclipse

Question

I downloaded a demo jar file  and would like to open it in eclipse  What I did is     import- Existing projects into workspace - select archive file   However  the eclipse returns  No projects are found to import    As command line  I type      java -jar projectDemo jar   This jar file just functions well  So it seems to me that jar file itself is OK  but how can I open it in Eclipse and modify this demo code  Thanks

User · Answer

A project is not exactly the same thing as an executable jar file.

For starters, a project generally contains source code, while an executable jar file generally doesn't. Again, generally speaking, you need to export an Eclipse project to obtain a file suitable for importing.

User · Answer

Firstly  it s necessary to know what is a jar file   From Oracle      JAR  Java Archive  is a platform-independent file format that   aggregates many files into one  Multiple Java applets and their   requisite components   class files  images and sounds  can be bundled   in a JAR file and subsequently downloaded to a browser in a single   HTTP transaction  greatly improving the download speed  The JAR format   also supports compression  which reduces the file size  further   improving the download time    As you can see     It has nothing to do with a Eclipse project  An Eclipse project can be a Java project  C   project and so on  It s just a self contain project that can be recognized and operated as an unit by Eclipse  The  class files are generally the main part of a jar file  It s impossible to view the source code  java file  unless you decompile the executable file  class file  by some tools  Take Eclipse for example  you can choose the plugin Eclipse Class Decompiler as the tool

User · Answer

Try JadClipse It will open all your  class file  Add library to your project and when you try to open any object declared in the lib file it will open just like your  java file   In eclipse- help-  marketplace -  go to popular tab  There you can find plugins for the same    Update  For those who are unable to find above plug-in  try downloading this  https   github com java-decompiler jd-eclipse releases download v1 0 0 jd-eclipse-site-1 0 0-RC2 zip  Then import it into Eclipse   If you have issues importing above plug-in  refer  How to install plugin for Eclipse from  zip

User · Answer

The jar file is just an executable java program  If you want to modify the code  you have to open the  java files

User · Answer

Since the jar file  executes  then it contains compiled java files known as  class files  You cannot import it to eclipse and modify the code  You should ask the supplier of the  demo   for the  source code    or check the page you got the demo from for the source code   Unless  you want to decompile the  class files and import to Eclipse   That may not be the case for starters

User · Answer

there is an Eclipse app called Import Jar As Project  I think it is quite simple and useful  https   marketplace eclipse org content import-jar-project mpc true amp mpc state

User · Answer

use java decompiler  http   jd benow ca   you can open the jar files   Thanks  Manirathinam

[java] how to open a jar file in Eclipse

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