This PR accumulates many refactorings and small improvements that I did while preparing the next change set of https://github.com/druid-io/druid/projects/2. I finally decided to make them a separate PR to minimize the volume of the main PR.
Some of the changes:
- Renamed confusing "Generic Column" term to "Numeric Column" (what it actually implies) in many class names.
- Generified `ComplexMetricExtractor`
* Rename io.druid to org.apache.druid.
* Fix META-INF files and remove some benchmark results.
* MonitorsConfig update for metrics package migration.
* Reorder some dimensions in inner queries for some reason.
* Fix protobuf tests.
* Various changes about druid-services module
* Patch improvements from reviewer
* Add ToArrayCallWithZeroLengthArrayArgument & ArraysAsListWithZeroOrOneArgument into inspection profile
* Fix ArraysAsListWithZeroOrOneArgument
* Fix conflict
* Fix ToArrayCallWithZeroLengthArrayArgument
* Fix AliEqualsAvoidNull
* Remove blank line
* Remove unused import clauses
* Fix code style in TopNQueryRunnerTest
* Fix conflict
* Don't use Collections.singletonList when converting the type of array type
* Add argLine into maven-surefire-plugin in druid-process module & increase the timeout value for testMoveSegment testcase
* Roll back the latest commit
* Add java.io.File#toURL() into druid-forbidden-apis
* Using Boolean.parseBoolean instead of Boolean.valueOf for CliCoordinator#isOverlord
* Add a new regexp element into stylecode xml file
* Fix style error for new regexp
* Set the level of ArraysAsListWithZeroOrOneArgument as WARNING
* Fix style error for new regexp
* Add option BY_LEVEL for ToArrayCallWithZeroLengthArrayArgument in inspection profile
* Roll back the level as ToArrayCallWithZeroLengthArrayArgument as ERROR
* Add toArray(new Object[0]) regexp into checkstyle config file & fix them
* Set the level of ArraysAsListWithZeroOrOneArgument as ERROR & Roll back the level of ToArrayCallWithZeroLengthArrayArgument as WARNING until Youtrack fix it
* Add a comment for string equals regexp in checkstyle config
* Fix code format
* Add RedundantTypeArguments as ERROR level inspection
* Fix cannot resolve symbol datasource
* add jq expression in the flattenSpec
* more tests
* add benchmark
* fix style
* use JsonNode for both JSONPath and JQ
* clean up
* more clean up
* add documentation
* fix style
* move jackson-jq version to dependencyManagement section. remove commented code
* oops. revert wrong fix
* throw IllegalArgumentException for JQ syntax error
* remove e.printStackTrace() that is forbidden
* touch
* Make Errorprone the default compiler
* Address comments
* Make Error Prone's ClassCanBeStatic rule a error
* Preconditions allow only %s pattern
* Fix DruidCoordinatorBalancerTester
* Try to give the compiler more memory
* Remove distribution module activation on jdk 1.8 because only jdk 1.8 is used now
* Don't show compiler warnings
* Try different travis script
* Fix travis.yml
* Make Error Prone optional again
* For error-prone compiler
* Increase compiler's maxmem
* Don't run Error Prone for benchmarks because of OOM
* Skip install step in Travis
* Remove MetricHolder.writeToChannel()
* In travis.yml, check compilation before tests, because it may fail faster