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 : commons-codec-1.6-jarjar.jar:
Step-1: Create a build.xml like follows:
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.<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"/></path><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"/></jarjar></project>
You can download all the files mentioned in above script and build.xml from here.
