- `./mvnw test ...` by its nature only runs unit tests, whose name is pattern of `*Test`, and it does never runs integration tests, whose name is patter of `IT*` or `*IT`, so in this PR we use `./mvnw clean test ...` to only run unit tests.
- `./mvnw integration-test ...` will run integration tests and unit tests, so we have `skipUTs` to control whether to skip the UT when running ITs, we already had this before.
  - As for ITs, we have two groups, one is normal tests without any `@Tag`s, the other one is slow integration tests, which is annotated with `@Tag("slow")`, so we divided the integration tests into two workflow jobs:
  - `./mvnw -DskipUTs=true clean integration-test -DexcludedGroups=slow ...` run the ITs but don't run the slow ITs and UTs, `-DexcludedGroups=slow` excludes tests annotated with `@Tag("slow")`
  - `./mvnw -DskipUTs=true clean integration-test -Dcheckstyle.skip -Dtest=${{ matrix.test.class }}` run the slow ITs (because `excludedGroups` is not set) one case at a time, by setting `-Dtest={{ class }}`, not run UTs,

* Remove agent codes and clean up

Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

* Upgrade dependencies and make the JDK11 compiling passed.

* Update license and fix license check file.

* Add CI for JDK11 compiling.

* Update doc.

* support build single module

* enforce maven version must greater than 3.6

* update build doc to support maven3.6+

Modify Eclipse and IDEA  steps

* Make an alternative method while cloning skywalking project and sync submodules

* Add language type for code block

* Intend code blocks under list block

* Make list number same

* Move a tip about building from source codes.
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

* mvnw proxy config

explanation about config proxy mvnw
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

* Add es7 support to docker

* Add es7 to github aciton workflow

* Rename dockerfile

* Update docker-compose

* Update matrix es name

* Set oap tag

* Add document

* Update How-to-build.md

* Change OAL generator tool to runtime.

Step 1. change project structure. API links and maven pom.

* Part of metrics class generation

* Metrcis class generated.

* Set up the basic structure of new OAL engine.

* Finish metrics generation.

* Support dispatcher generation.

* Format codes.

* Generate dispatcher all methods.

* Implement disable in hardcode.

* Clear up

* Fix compile startup.

* Update license and document of new OAL engine.

* Fix rat.

* Disable class output in default

* Copy from @kezhenxu94 's test PR, https://github.com/apache/skywalking/pull/3110

* Wait for the mount command to finish

* setup your idea

* add anchors

* fix

* Update docs/en/guides/How-to-build.md
Co-Authored-By: Nkezhenxu94 <kezhenxu94@163.com>

* Update docs/en/guides/How-to-build.md
Co-Authored-By: Nkezhenxu94 <kezhenxu94@163.com>

* Adjust pom plugin position and add docs

* Polishing

* Update as requested

* Implement the base of config API module.

* Finish configuration module codebases w/o tests, revert some changes.

* Finish mock tests.

* Add new gRPC service for configuration.

* Make gRPC configuration sync provider works.

* Add database slow statement dynamic setting.

* Finish the dynamic configuration service.

* Fix version.

* Update docker building of oap server

 * generating appliation.yml according to enviroment variables
 * adding Makefile to build binary and docker image

* Update ui docker

* Update docker-compose

* Update document

* Update document

* Merge from master

* Reset skywalking-ui

Update all "incubator-skywalking" to "skywalking" ,"incubator-servicecomb-java-chassis" to "servicecomb-java-chassis" correctly, and ".gitmodules" will update at #2531 (#2548)

* Move all receiver proto files together, in case the class conflict in gogoproto.

* Add jaeger proto and its dependency proto. Also license provided.

* Fix rat.

* Support grpc exporter.

* Support scope(all) metric export and finish document.

* Close exporter even in local debug env. And fix CI.

* Remove the system.out

* Fix absent 4.

* Support subscription from remote.

* Add the doc

* Update application.yml

* Make scope meta configurable.

* Fix test cases in ci.

* Change step 1

* Refactor step 2

* Other compile issue done. Prepare the generator changes.

* Revert some wrong changes to Istio receiver.

* Step 3, make compile pass.

* Try to make CI passed.

* Add a check.

* Fix generated code style

* Provide new and extendable dispatcher generator tool

* Fix startup.

* Can't guarantee the dispatchers are always existing. Put explicit comments at there to avoid confusion, since this is different with old version.

* Fix a H2 query for endpoint search.

* Fix a wrong mysql alarm query.

* Provide new document and `generate-tool-grammer` module.

* Add missing last section of document.

* Fix typo

* Relocate the @ScopeDeclaration annotation, make it more sense. Also remove the useless @SourceType annotation. And adjust document for these changes

* ScopeDeclaration can be used once for each class only, now.

* Move oal tool back into main repo, and fix compile issue.

* Fix two bugs.

* Remove all generated codes.

* Make all oal generated codes out of source control.

* Make mvn compile and package work.

* Fix test cases.

* Make compile right and provide new documents.

* Remove an unnecessary tokens file.

* Lock oracle and resin plugins version.

* Move resin and oracle plugin to openskywalking

* Restore submodule active.

* Add another submodule active command.

* Remove the wrong test cases in release and fix some doc issues.

* [maven-release-plugin] prepare release v6.0.0-alpha

* [maven-release-plugin] prepare for next development iteration

* Fix some doc

* update build md

* add   generated-sources  protobuf  in  build.md

* Moves to Maven wrapper to stabilize the version in use

This will ensure those building will have similar experience due to
having a fixed maven version.

* Updates most plugin versions and removes redundant configuration

* Sets up build enforcement for JDK 1.8 until further work occurs

* Update How-to-build-CN.md

* Update How-to-build-CN.md

* Update How-to-build.md

* Update docs for alpha release

* Delete a comma.

* Update How-to-build.md

* Add data-set licenses file

* Rename LICENSES-data-set to LICENSE-data-set

* Update LICENSE

* Remove fastclick from LICENSE

* Make the git submodule command to be a maven profile plugin. Let this command not execute by default install command.

* [maven-release-plugin] prepare release apm-5.0.0-alpha

* [maven-release-plugin] prepare for next development iteration

* Product name is not correct

* Add more documents for release.

* Change profile id.

* Add CHANGES file in distribution file.

* Revert "[maven-release-plugin] prepare for next development iteration"

This reverts commit ac815019.

* Revert "[maven-release-plugin] prepare release apm-5.0.0-alpha"

This reverts commit 095597c9.

* Add rat plugin to check dependency license and add license head into missing files.

* Fix docs.

* Exclude web ui config file.

* Next release guide.

* UI update.

* Update docs.

* Build source shell.

* Update docs and source release.

* remove .sha256 requirement.

* Update How-to-release.md

* Update How-to-release.md

* Update build doc.

* Update docs.

* Update How-to-release.md

* Update How-to-release.md

* Update docs for alpha release

* Delete a comma.

* Update How-to-build.md

* Add data-set licenses file

* Rename LICENSES-data-set to LICENSE-data-set

* Update LICENSE

* Remove fastclick from LICENSE

* Make the git submodule command to be a maven profile plugin. Let this command not execute by default install command.

* [maven-release-plugin] prepare release apm-5.0.0-alpha

* [maven-release-plugin] prepare for next development iteration

* Product name is not correct

* Add more documents for release.

* Change profile id.

* Add CHANGES file in distribution file.

* Revert "[maven-release-plugin] prepare for next development iteration"

This reverts commit ac815019.

* Revert "[maven-release-plugin] prepare release apm-5.0.0-alpha"

This reverts commit 095597c9.

* Add rat plugin to check dependency license and add license head into missing files.

* Fix docs.

* Exclude web ui config file.

* Next release guide.

* UI update.

* Update docs.

* Build source shell.

* Update How-to-build-CN.md

* Update How-to-build.md