If I kill an Android app with System.exit(...), does it matter what status code I pass? I couldn't find any documentation on whether Android just ignores it or whether certain ones lead to any error messages for example or have any other meaning.
This is the exit code returned by the process when it finishes; Android however does not care, but know that the error code should never be higher then 255.
Here is a list of standard exit codes - some process may use their own codes.
0 Clean Exit
1 General Error Catchall
2 Misuse of shell builtins
126 Command invoked execution error
127 Command not found
128 Invalid exit argument?
130 Termination by Control-C
255 Exit status unknown
Android does not care, no. This is a java thing -- you can use them for your own debugging etc etc.
Here's an example of system exit codes: http://www.opensource.apple.com/source/Libc/Libc-320/include/sysexits.h
But pretty much, anything > 0 means that its an abnormal exit. You can set it to whatever you want, but I'd just stick to 0 unless you're interacting with other things.
It just seems to be the accepted convention.
来源：https://stackoverflow.com/questions/30226842/does-android-care-about-exit-status-code-passed-to-system-exit