Dealing with Java Hell using JarJar life boat

Okay, so I wanted to use Hex.encodeHexString method from org.apache.commons.codec.binary.Hex (commons-codec-1.6.jar)library to generate encoded singnature. I was able to do this in plain Java, but not in Android. I googled for a while and found out this ticket about Android not supporting the latest versions of commons-codec-1.6.jar.The solutions was to use magical "jarjar" ! But How ??? Again, I googled and come across this and this, and I came up with solution to solve mystery of using  Hex.encodeHexString method in code running on Android (Dalvik VM). Android uses old version of commons-codec jar which doesn't define org.apache.commons.codec.binary.Hex.encodeHexString method signature. Even if you add new commons-codec-1.6.jar to build path of project, code will try to refer to built-in commons-codec not the new one that you added in build path. But, if you change the package name/namespaces for commons-codec-1.6.jar, then you can easily reference from your code and finally can use Hex.encodeHexString. So, you have to create a custom jar with modified package name structure.

Here is how you can spin a new custom jar, say

Step-1: Create a build.xml like follows:
<project name="generate-jarjar">
    <property name="jarjarfile" value="commons-codec-1.6-jarjar.jar"/>
    <path id="classpath">
      <pathelement location="jarjar-1.4.jar"/>
      <pathelement location="asm-2.2.3.jar"/>
    <taskdef name="jarjar" classname="com.tonicsystems.jarjar.JarJarTask"   classpathref="classpath"/>
    <delete file="${jarjarfile}"/>
    <jarjar destfile="${jarjarfile}">
    <zipfileset src="commons-codec-1.6.jar"/>
    <rule pattern="org.apache.**" result="org.jarjar.apache.@1"/>
Step-2: Run command "ant" from command line. This build script will generate a new jar  commons-codec-1.6-jarjar.jar, which you can add in your build path and use this new jar to import from.

You can download all the files mentioned in above script and build.xml from here.


  1. HI Priyanka ,. Could you please suggest me something on the following .

    I have com.efaxdeveloper.util.jar and there is xrcers package in it used by the other classes in the same jar . There is another verion of xrcers jar in my pom.xml used by other application in my project . This gives conflicts . I replaced the xrcers package in com.efaxdeveloper.util jar with the newer version . now How I change their reference in classes . Or is there any othere solutions to it . Please let me know if there is any confusion.
    Thanks !


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