[SPARK-14359] Unit tests for java 8 lambda syntax with typed aggregates

[ericl]

What changes were proposed in this pull request?

Adds unit tests for java 8 lambda syntax with typed aggregates as a follow-up to #12168

How was this patch tested?

Unit tests.

[ericl]

@rxin

[JoshRosen]

[warn] Java 8 tests will not run because JDK version is < 1.8.

I think that the default PR builder might still be running Java 7 because my first attempt at switching to Java 8 seemed to have introduced some transient flakiness. I'm going to go ahead and re-push the config changes to enable the Java 8 tests and will fix any flakiness that crops up. I'll email dev@ now to let folks know.

[JoshRosen]

Jenkins, retest this please.

[SparkQA]

Test build #55014 has finished for PR 12181 at commit cc745c5.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
  • public class Java8DatasetAggregatorSuite extends JavaDatasetAggregatorSuiteBase
  • public class JavaDatasetAggregatorSuite extends JavaDatasetAggregatorSuiteBase
  • class JavaDatasetAggregatorSuiteBase implements Serializable

[rxin]

can you define two java classes in one file?

[ericl]

Seems fine as long as there is only one public class.

[rxin]

weird you got two here.

[SparkQA]

Test build #55022 has finished for PR 12181 at commit cc745c5.

• This patch passes all tests.
• This patch does not merge cleanly.
• This patch adds the following public classes (experimental):
  • public class Java8DatasetAggregatorSuite extends JavaDatasetAggregatorSuiteBase
  • public class JavaDatasetAggregatorSuite extends JavaDatasetAggregatorSuiteBase
  • class JavaDatasetAggregatorSuiteBase implements Serializable

[rxin]

LGTM - merging in master.