What is Odex & Deodex Explained in English | FREE UP YOUR INTERNAL STORAGE AND SPEED UP YOUR ANDROID
 In this article, we’ll try to explain what odexed
  and deodexed means, and what implications does
  it bring to a casual user.
  
  So let's start 
  
  
  WHAT IS AN ODEX FILE?
  In Android file system, applications come in
  packages with the extension .apk. These
  application packages, or APKs contain certain
  .odex files whose supposed function is to save
  space. These ‘odex’ files are actually collections of
  parts of an application that are optimized before
  booting. Doing so speeds up the boot process, as it
  preloads part of an application. On the other
  hand, it also makes hacking those applications
  difficult because a part of the coding has already
  been extracted to another location before
  execution.
  THEN COMES DEODEX
  Deodexing is basically repackaging of these APKs in
  a certain way, such that they are reassembled into
  classes.dex files. By doing...