* Upgrade dependencies and make the JDK11 compiling passed.

* Update license and fix license check file.

* Add CI for JDK11 compiling.

* Update doc.

* Move spring webflux into optional plugin

* Fix compile check

* Fix check style

* Adjust code

* add docs

* Update docs/en/setup/service-agent/java-agent/README.md
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

* Fix sampling and Kafka reporter conflicting.

* Remove legacy codes.
Co-authored-by: Nkezhenxu94 <kezhenxu94@apache.org>

* [maven-release-plugin] prepare release v8.1.0

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

* [maven-release-plugin] prepare release v8.0.0

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

* Remove all shardingsphere cases.

* [maven-release-plugin] prepare release v7.0.0

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

Motivation:

Review code styles with some bots automatically.

Modifications:

Set up ReviewDog in GitHub Action to review code style.

Add more check rules to checkstyle plugin.

Result:

Obvious code styles can be reviewed and commented automatically.

### Motivation:

Clean up unused codes and migrate to JDK8.

### Modifications:

- Remove unused codes.

- Close unclosed I/O stream.

- Remove meaningless comments.

### Result:

- No unnecessary codes concerns.

- No resources leak.

### Motivation:

Reduce footprint when tagging spans with the deprecated API: `AbstractSpan#tag(String, String)`.

### Modifications:

- Adopt [prototype pattern](https://en.wikipedia.org/wiki/Prototype_pattern) to create `Tag`, prevent from creating too many `StringTag` instances and `GC`ed.
- Replace `AbstractSpan#tag(String, String)` with `AbstractSpan#tag(AbstractTag, String)`.

### Result:

- Footprint is reduced.

* Optimize trace ignore plugin

* Add license for FastPathMatcher

* Boot again after setting config in test

* Fix check style

* Fix typos
Co-authored-by: Nkezhenxu94 <kezhenxu94@163.com>

* Kotlin coroutine plugin write in Java
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

* [Feature] Add tag annotation to allow tagging span with annotation

* Use repeatable annotation syntax and add docs and example codes

* Fix failed unit test

* Add play-scenario

* Set play plugin as default
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>
Co-authored-by: NWeiyi Liu <liuweiyi@cmss.chinamobile.com>

* Move Armeria plugin to default plugin list

* Move Armeria plugin to default plugin list
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

* Move Webflux plugin into default list.

* Fix a typo.

* Move lettuce into default plugin

* Fix maven pom

* [maven-release-plugin] prepare release v6.6.0

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

* webflux-reactive

* add support version comment, modify gateway

* add test case, modify name

* add docs

* remove healthCheck

* plugin code

* NPE FIX

* [maven-release-plugin] prepare release v6.5.0

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

* spring-cloud-gateway traceid does not transmit #3411

skywalking-version:6.5.0

spring-gateway-version:2.1.2

Error Description:

 Customize the filter, traceid does not transmit.

 "ServerWebExchangeDecorator" is a transport chain,His structure should be like this：

	 serverWebExchangeDecorator
	    -----(ServerWebExchangeDecorator)delegate
		    ------(ServerWebExchangeDecorator)delegate
			  ------.....
			   -----(DefaultServerWebExchange)delegate
  In the current source code, there is no deep search, but only the next level. When there are multiple custom filters, you get an error.

Repair method:

  Look for "delegate" of "ServerWebExchangeDecorator" recursively until "DefaultServerWebExchange"

* spring-boot-webflux traceid does not transmit #3411

spring-boot-starter-webflux-version:2.1.6

Error Description:

Customize the filter, traceid does not transmit.

"ServerWebExchangeDecorator" is a transport chain,His structure should be like this：

 serverWebExchangeDecorator
    -----(ServerWebExchangeDecorator)delegate
	    ------(ServerWebExchangeDecorator)delegate
		  ------.....
		   -----(DefaultServerWebExchange)delegate

In the current source code, there is no deep search, but only the next level. When there are multiple custom filters, you get an error.

Repair method:

Look for "delegate" of "ServerWebExchangeDecorator" recursively until "DefaultServerWebExchange"

* checkStyle

* [maven-release-plugin] prepare release v6.4.0

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

* Fix the zookeeper plugin has many nodes in the cluster case

* support version

* Support play 2.x 

* update gateway

* Unified http status code usage

* fmt

* [maven-release-plugin] prepare release v6.3.0

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

* POC: Intercept successfully.

* Refactor codes

* Build the new core

* Setup the new core.

* Push the javassist version to 3.23.2-GA, as it is the last version supports JDK 1.6 compile, according to https://github.com/jboss-javassist/javassist/blob/rel_3_23_2_ga/pom.xml#L149-L160

* Finish the all codes.

* Document updated for bootstrap instrumentation.

* Add a notice to document.

* Remove unexpected file.

* Set javassist version right. Add judge in core interceptors

* Fixe no log bridge implementation