* improve auto connect

* add config

* use int instread of atomic

* update format

* update doc

* update var name and doc

* fix

* Unified http status code usage

* fmt

* support elasticsearch address configuration with http scheme.

* update logical.

* Modify the thread pool of grpc server.

* add license header

* make param confingable

* Add sharing and Jaeger config.

* Remove grpc thread config from yml

* Remove the meta file

* Add dependency licenses check 

* Update backend-storage.md

* Update backend-storage.md

* Update ES-Server-FAQ.md

* improve AsyncSpan API: make #asyncFinish and #prepareForAsync can not invoke more than once
make the API more strong: make the plugin code bug fail-fast

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

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

* GC time metrics should be total time.

* Add it to change log.

* FYI @hanamily you missed to change this in self observability.

* fix changes.md typo

* fix typo

* Add changelog for 6.3.0 release.

* Update CHANGES.md
Co-Authored-By: Nkezhenxu94 <kezhenxu94@apache.org>

* Update CHANGES.md

The current latency of the test service is too slow, causing it's not counted and
the query result is 0, this patch increases the latency intentionally by sleeping
1 second

* Fixed java agent cannot trace gRPC stream service

* add http

* update plugin

* Add StaticMethodsAroundInterceptor to be injected.

* move to options plugin

* move folder

* update pom

* support https

* add witness class

* Make JDK9-11 available for bootstrap instrumentation

* Remove temp folder of old bootstrap instrumentation requirement.

* remove witness ,work for jdk6,7,8,9,10,11

* Make JDK 12 works.

* move jdk-http-plugin to bootstrap-plugins folder

* add httpsclient

* update README.md

* Support upgrade backend w/o rebooting agents

* Make JDK9-11 available for bootstrap instrumentation

* Remove temp folder of old bootstrap instrumentation requirement.

* correct 3rd default alarm rule description

* unit change: 1000ms -> 1s

* Remove javassist dependency

*   Finish the PR.

* Change doc title level.

* Remove the duplicated codes.

* Support etcd configuration.

1. All the inventories add last_update_time attribute,  delete the mapping_last_update_time attribute in service inventory. (#3168)

2. Fixed the service inventory and net address inventory update bugs.

* 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

* Don't build JavaDoc since we don't host JavaDoc pages

* Update Jenkinsfile

* Revert back to where it's single-threaded job

* Feature of database session

* Make it configurable.

* Change the metrics process flow.
before: metrics entrance -> aggregate worker -> remote worker -> trans worker -> minute, hour, day, month persistence worker -> storage
after: metrics entrance -> aggregate worker -> remote worker -> minute persistence worker ->  trans worker -> hour, day, month persistence worker -> storage

* IntKeyLongValueHashMap instead of IntKeyLongValueArray.

* Make the OAP server can't startup.

* Finish

* Rename the method and fixed some test case issues.

* Rename field.

* no message