"The filename, directory name, or volume label syntax is incorrect" when signing Android app

Question

When I compile my Android app in release mode and try to sign it, I get the following error:

The filename, directory name, or volume label syntax is incorrect

I set key.store in ant.properties to a relative path to my keystore file. There are no spaces in the file name or path. I'm certain that I'm using the correct password for the keystore because I can use the keytool -list command to view it. What else could be causing this error?

Update:

When I use an absolute path I get the following error message:

Value for 'keystore' is not valid. It must resolve to a single path

Answer 1

The cause of the problem turns out to be very trivial and difficult to catch. I had quotes around the value of the key.store property in my ant.properties file. Apparently something in the build chain includes the quotes as part of the property's value. After removing the quotes, I compiled and signed my app just fine.