The mapper and reducer must be written in the language specified by the Source Code Language selection box, following the appropriate format for that language. (See later chapters for examples and API specifications for each language.) Each piece of code can be submitted in either of two ways:
Upload: Upload source code from the local machine to the web interface. This is useful for long source code listings, or ones that need to be saved for future use.
Direct Input: Input code directly into the text box. Code submitted this way might be lost if you refresh the page, navigate away, etc., depending on your browser.
