On the Android platform, the execution file of dalvik vm is packaged in apk format. Eventually, the runtime loader will decompress and get the security access related to the permission branch in the compiled androidmanifest.xml file, but there are still many security restrictions. If you transfer the apk file to the /system/app folder, you will find that the execution is unrestricted. The installed file may not be in this folder, but in androidrom, the apk file of the system will be placed in this folder by default, and it has root permission.
Its file structure has five layers:
1.META-INF\ (note: it can often be seen in Jar files);
2.res\ (note: the directory where the resource files are stored);
3.AndroidManifest.xml (note: program global configuration file);
4.classes.dex (note: Dalvik bytecode);
5.resources.arsc (note: compiled binary resource file).
Installation: Use the mobile assistant software or install it in the mobile phone.