Improve error messages for instantiation errors on arrays and for programs without data sinks.
Add write mode to data set write function.
map operator test
flatMap operator test
Testcases for the CoGroup operator in the new Java API
Change return type of the CoGroup combine functions to a single value.
Add default empty method stub for combiners in CoGroup functions.
Add semantic property fields to single- and two-input udf operators.
Lots of comments.
Union implementation for new java api, with simple UnionIT testcase
Rewrite TypeExtractor to support more types and complex type structures. Possible Exceptions are now more user-friendly.
Fix of JVM 6 related bug and enhancement of 2 other corner cases.
Adjusted TypeExtractorTest for updates CoGroup combiner signatures.
Added comments and checks to the StringUtils
Added comments to the Tuple classes.