SD: Various Clean-Ups

• *.java: Add missing JavaDoc. Make JavaDoc comments more consistent in typography and wording and use of abbreviations. Fix code indenting. Add "final" modifier where appropriate. Eliminate some duplicate code. Rename some variables for enhanced consistency and clarity. Add missing serial version UID. Remove unused imports. Break overly long lines. Replace discouraged generic "RuntimeException" with more specific "ServiceException". Make use of String.format() in favour of string concatenation when creating messages with parameters.