upstart System.in.read() crashes the process? - upstart

Question

My java application is only this:
System.out.println("waiting for input...");
PrintWriter writer = new PrintWriter("/home/pc/test-java.txt", "UTF-8");
writer.println("The first line");
writer.println("The second line");
writer.close();
System.in.read();
The file is created just fine, then the process seemingly dies without warning. I could not find anything in the docs that would explain this behavior. Am I not allowed to wait for input at all? How would upstart know that I'm trying to read input and prevent it? Why does it care? I'm only upstart script testing here.
Here is the full script:
start on runlevel [2345]
stop on runlevel [016]
respawn
respawn limit 2 5
script
exec java -jar /home/pc/test-0.0.1-SNAPSHOT.jar
end script

Answer 1

Some relevant snippets from the Upstart documentation for the console stanza:
For all versions of Upstart prior to v1.4, the default value for console was console none. As of Upstart 1.4, the default value is console log.
6.5.1 console log
Connects standard input to /dev/null.
6.5.2 console none
Connects the job's standard input, standard output and standard error file descriptors to /dev/null.
6.5.3 console output
Connects the job's standard input, standard output and standard error file descriptors to the console device.
So, in all versions of Upstart, stdin is mapped to /dev/null by default. Thus, System.in.read() immediately reads end-of-file (EOF) and returns.
To get the behaviour you seem to want, add either console output or console owner to your Upstart job definition:
start on runlevel [2345]
stop on runlevel [016]
respawn
respawn limit 2 5
console output
# OR
#console owner
script
exec java -jar /home/pc/test-0.0.1-SNAPSHOT.jar
end script