* add logstash logback plugin
* add logstash logback plugin, set pom provided, refine logback doc
* refine logstash logback doc
* refine the comment
* remove the app_id that not related to SkyWalking
* remove tag @date for CI error: unknown tag: date
* add description for iLoggingEvent for ci warning: no description for @param
* Support op group name in agent config core.
* Provide core API for operation name grouping, rest template plugin update, and doc update.
* Fix doc
* Fix test case.
* Fix missing changes.
* add shuyun to powered-by.md (#3341)
* add shuyun to powered-by.md
* update powered-by.md
* Remove static method.
* Add cached writer so we need not call whole method.
* Make writer volatile.
* Make writer to WRITER.
* Rewrite the writeFactory for add the cached writer and keep the unit tests stable.
* Give the default writer.
* Remove volatile.
* Stabilize unit test
The FileWriterTest creates files in the source directory(failed to
delete them due to a bug in the `deleteDir` method), making
them being checked by checkstyle plugin and failed to pass.
* Seperate compilation step
* Refactor open edge.
* Make refactor works.
* Revert log back.
* Remove unnecessary codes.
* Open edge for all internal binding interceptors.
* Add document about JDK 9+ module.
* Change bytebuddy to 1.10.1(unreleased)
* Change document
* 1. Adopt the latest bytebudy changes(snapshot only), commit b609711564.
2. Remove disruptor by ArrayBlockingQueue, because Disruptor can't work in both JDK 8(1) and 9-12, if we don't add `--add-modules jdk.unsupported`
3. Doc update.
* Update README.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
* 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
* servlet 2.5
* method exist
* update MethodUtil
* Update MethodUtil.java
Add a comment to the new core util method. @candyleer I am concerning this method will be used widely even unnecessary.