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

Implicit use of the platform default charset, which can result in differing behaviour between JVM executions or incorrect behavior if the encoding of the data source doesn't match expectations.
Co-authored-by: Nzhang-wei <pknfe@outlook.com>
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

* Add cache for maven local repo.

* FIx formats.

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

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

* Fix JdkObsolete issue

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

Inner class is non-static but does not reference enclosing class

ref: https://errorprone.info/bugpattern/ClassCanBeStaticCo-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

Non-exhaustive switch; either add a default or handle the remaining cases: VALUE, UNKNOWN
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

ref: https://errorprone.info/bugpattern/GetClassOnEnum

* Upgrade dependencies and make the JDK11 compiling passed.

* Update license and fix license check file.

* Add CI for JDK11 compiling.

* Update doc.

* Polish comments of the meter at the agent side.

* Fix code style.

* Add a muse configuration file

A muse configuration and file is necessary to educate the MuseDev CI
system on how to build Skywalking.

* Exclude .muse/* files from license check

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

* modify witness class

* modify witness class & add test case

* replace DB_STATEMENT to DB_BIND_VARIABLES & remove executeMethod prefix

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

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

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