Problem scenario: You are trying to upload a file to S3 but get an error. You use a command like this:
curl -T /path/to/sourcefile.java http://s3.amazonaws.com/my.bucket/sourcefile.java
You get an error in XML that includes "The specified key does not exist."
Solution: Check the path to your source file. Verify your source file is there with the name you expect it to be.