1. A method for managing an Android application package (hereinafter referred to as “APK”) file in the Android platform including: a stage in which a file reader reads an original .dex file in the APK file; a stage in which a file modifier modifies the original .dex file which the file reader has read and stores the modified .dex file in a readable folder in the APK file; a stage in which a file creator accesses the folder to read and restore the original .dex file, creates a temporary .dex file that is loaded onto memory and adds the temporary .dex file to the APK file in order to create a protected APK file; a stage in which a file executer reads from the folder and restores, if the Android platform requests the protected APK file to be executed, the modified original .dex file by executing the temporary .dex file; and a stage that loads the restored original .dex file onto memory and executes the protected APK file, wherein the stage that stores the modified .dex file in a readable folder in the APK file reads the original .dex file and compresses or encrypts the original .dex file then stores the compressed or encrypted original .dex file in the folder, and wherein the stage that creates the protected APK file creates the temporary .dex file creating code that accesses, by a function the Android platform provides, the folder, wherein the stage that creates the protected APK file reads and restores the modified original .dex file and loads the restored .dex file onto memory.