What is a dex file and how do I open a dex file?
DEX, or Dalvik Executable is a file format that contains compiled code written for Android and can be interpreted by the Dalvik virtual machine. DEX files can be created manually or by automatically translating compiled Java programs. Multiple DEX files are zipped into a single APK, which serves as the final Android application file. Google originally developed the DEX file format, and the Android OS (also developed by Google) is a Unix-based platform for supported mobile devices. Programs are commonly written in Java and compiled to bytecode for the Java virtual machine, which are then translated to Dalvik bytecode and stored in .dex file format. The Dalvik virtual machine is an application service implemented into the Android OS to interpret the compiled code stored in a DEX file. The Dalvik executables may be modified again when installed onto a mobile device. In order to gain further optimizations, byte order can be swapped in certain data, simple data structures and function libraries may be linked inline, and empty class objects may be short-circuited. Developers with Microsoft Windows-based systems or Mac platforms can create Android applications with DEX files by using the Google Android SDK software. Compiled Java applications may also be translated into Android programs with associated DEX executable files. Multiple DEX files are stored in a distributive package saved in the APK format, and these APK files are the actual Android applications.
Relevant dex file links:How to open dex file on Youtube
How to open dex file on Wikipedia
How to open dex file on Microsoft.com