Convert class file to dex file

Question

How to convert class file to dex file in android? Is there any way?

Answer 1

Invoke "dx" command with "--dex" option like the following.

dx --dex --output=<output-file> <input-file>

"dx" command is contained in Android SDK. The location of the command varies. Try to search:

<SDK-HOME>/platform-tools/
<SDK-HOME>/platforms/<platform>/tools/

"dx --dex" can accept some options. For example, "--no-strict" option will skip checking whether path names of input class files match the declared package/class names, so you'll get a different result for WebService.class if you invoke dx with this option. Probably, "--keep-classes" option is useful if you want to use jar files on both Android and Java SE. Without "--keep-classes" option, dx command replaces all .class files in an input jar file with one file named "classes.dex", but with "--keep-classes" option, input .class files also go into the ouput file as well as classes.dex.

ex:
  dx --dex --keep-classes --output=output.jar input.jar

I read the source code of dx and listed up the command line options with some explanation at the following page.

Usage of dx --dex:

http://darutk-oboegaki.blogspot.com/2011/03/usage-of-dx-dex-dx-dex.html

Answer 2

Use dx.