The most recent JavaDoc for your specific system is available under:
http://[siteURL]/api/docs/javadoc/where siteURL is the domain of your email platform.
Several constant values are used in code examples throughout the help files, usually following the form APIConstants.CONSTANT_NAME. You can find those values defined, as well as the values for all integer return codes used by the API, in the JavaDocs.
Between system releases, some method signatures may change, such as return values and error handling. Please use the JavaDocs for the most current method calls and return values.