* Make sure heartbeat working always. cc @liuhaoyang make sure .net agent hasn't this issue.

* FIx CI.

* Fix mesh receiver doesn't update heartbeat.

* Fix bug of mesh heartbeat and rest receiver.

* Fix issue: opencensus is included in agent without shade. @tuohai666

* Revert reset feature.

* Set default dist alarm settings and make dist package setting files right.

* Support empty list.

* Manually trigger agent registration and write registration status to file

* Delete unused variables

* Code optimization, encapsulating some methods

* add clear DataCarrier function

* revert SkyWalkingAgent

* Optimize code and logic, including updating applicatin_id in unRegisterOperationNames

* Server end metadata loss notification

* Server end metadata loss notification

* fix file stream close and other problem

* revert to old

* fix some bug
Signed-off-by: NLiu-XinYuan <879928098@qq.com>

* fix some bugs in agent reset

* add close inputStream and fileChannel and fix some bug

* fixed some bugs

* update 5.x grpc version form 1.10 to 1.14 and  Solve the resulting guava and log4j version conflicts

* Specify guava version 20.0

* update parrent pom guava version

* Fix bug stop stopSpan when not createSpan

* Fix bug stop stopSpan when not createSpan

* change the agent log level to millisecond

* add the function of the specified-agent-config

* Update README_ZH.md

* Use -D  to set the specified config path

* add docs

* update docs

* change method name

* add link

* change the function name

* change the key

* format doc

* Fix bug stop stopSpan when not createSpan

* Fix bug stop stopSpan when not createSpan

* change the agent log level to millisecond

* Fix bug stop stopSpan when not createSpan

* Fix bug stop stopSpan when not createSpan

* change the agent log level to millisecond

* [Agent] Provide plugin for Elasticsearch 5.x

Add [Agent] Elasticsearch transport client plugin

fix component name

add elasticsearch component

add elasticSearch component into component-libraries.yml

* update support list

* update PlainListenableActionFutureInterceptor.java

* fix set span attributes

* clear runtimeContext

* remove extra plugins

* 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

Remove collector.servers and collector.direct_servers, and add collector.backend_service setting. cc @ascrutae

* add activemq-plugin

* fix  update ActiveMQConsumerInstrumentation Enhance another class

* refacor ActiveMQConsumerInstrumentation code

* support both  topic and queue

* clear the code

* add UnitTest add fix bug

* fix obtain url  bug

* Refactor the ActiveMQProducerInstrumentation code

* fix bug

* fix ConstructorInterceptor BUG

* add Licensed

* Update application.yml

Restore configuration

* Restore configuration

* perfect test

* fix

* fix License

* fix  Project Files

* fix import class in instrumentation

* fix test case

* fix java doc

* fix  Trigger CI

* fix ActiveMQConsumerAndProducerConstructorInterceptorTest

* delete unit test

* fix

* fix

* fix  folder directory problem

* Delete ActiveMQConsumerInstrumentation.java

* add activemq-plugin

* fix  update ActiveMQConsumerInstrumentation Enhance another class

* refacor ActiveMQConsumerInstrumentation code

* support both  topic and queue

* clear the code

* add UnitTest add fix bug

* fix obtain url  bug

* Refactor the ActiveMQProducerInstrumentation code

* fix bug

* fix ConstructorInterceptor BUG

* add Licensed

* Update application.yml

Restore configuration

* Restore configuration

* perfect test

* fix

* fix License

* fix  Project Files

* fix import class in instrumentation

* fix test case

* fix java doc

* fix  Trigger CI

* fix ActiveMQConsumerAndProducerConstructorInterceptorTest

* delete unit test

* fix

* fix

* fix  folder directory problem

* Delete ActiveMQConsumerInstrumentation.java

* Fix RuntimeContext cannot store anything when the trace is not create

* Add RuntimecontextSnapshot and remove debug info

@lemon @ascrutae I change the proto file path for preparing 6.0, but didn't change .net namespace. But I think if you sync the protocol submodule, you still need some changes.

* Change version 

* fix #1274

* Allow use SkyWalking plugin to override service in Agent core.

* Fix CI.

* Remove duplicate plugin load.

* Add test cases for new plugin boot service machanism.

* commons testcase

* some ui module query testcase

* add testcase

* fix some checkStyle issue

* add some null testcase

* remove

* add license

* fix author error

* remove invalid tag @date

* add license which has been missed

* add jdk-cross-thread-plugin

* Because of key issue, system env override can't be supported.

* Override value only in supported types. Int, String, Long, Boolean.

* Add client side token.

* Fix ci.

* Fix most codes of token auth at both sides.

* Add settings in config files.

* Make auth interceptor doesn't throw expcetion.

* Update AuthenticationSimpleChecker.java

* Update AuthenticationActivator.java

* Revert "Update AuthenticationActivator.java"

This reverts commit 0935f18fd6802ab84c12e0609c21ef753ff51be3.

* Merge branch 'feature/token-auth' of https://github.com/apache/incubator-skywalking into feature/token-auth

# Conflicts:
#	apm-collector/apm-collector-agent/agent-grpc/agent-grpc-provider/src/main/java/org/apache/skywalking/apm/collector/agent/grpc/provider/AuthenticationSimpleChecker.java

* Fix Auhentication token works incorrect (#1001)

* Fix Auhentication token works incorrect

* Change way to build GRPC Channel

* Response an empty header when auth fails.