* Add more comments in the core module, should help the source code readers a lot.

* Fill some comments for core.

* Fix a comment issue.
Co-authored-by: Nkezhenxu94 <kezhenxu94@163.com>

* extract duplicated method

* change while loop to if since once rs.next() return false, it will never return true for the following calls

* simplify if() return true; return false pattern

* fix compilation
Signed-off-by: Nliqiang.clq <liqiang.clq@alibaba-inc.com>

* Make Profile entities could be disable by OAL

* support gRPC hook.

* revert submodule commit.

* revert submodule commitid.

* finish logical.

* remove author anonatation.

* fix ci.

* revert submodule.

* update logical.

* update logical.

* update logical.

* fix

* fix

* fix empty settings.

* fix.
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: Nkezhenxu94 <kezhenxu94@163.com>

* new line before package

* Update codeStyle.xml
Co-authored-by: Nkezhenxu94 <kezhenxu94@163.com>

* Update powered-by.md

* Update powered-by.md

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

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.

* provide profile analyze query
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

* test/plugin/scenarios/elasticsearch-7.x-scenario/support-version.list

* update elasticsearch-7.x agent support version.
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

* Add trace log

 * Trace alarm rule reader
 * Trace the process of running alarm rule, especailly the moving of window
 * Add toString method to relevant class for tracing

* Remove unused importsC

* Revert "Remove unused importsC"

This reverts commit 395e1678

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

* Make an alternative method while cloning skywalking project and sync submodules

* Add language type for code block

* Intend code blocks under list block

* Make list number same

* Move a tip about building from source codes.
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

* Change profile stack element to single level, not using tree

### 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.

* provide profiled segment query
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>
Co-authored-by: NAirTrioa <44222967+AirTrioa@users.noreply.github.com>

* Refactor ConfigInitializer

* Rename some variable names and add some java docs
Co-authored-by: Nkezhenxu94 <kezhenxu94@163.com>
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

[BUG]Fix the bug of port identification failure when connecting Oracle with Sid mode (JDBC: Oracle: thin: @ < host >: < port > / < Sid >) (#4320)

* [BUG]Fix the bug of port identification failure when connecting Oracle with Sid mode (JDBC: Oracle: thin: @ < host >: < port > / < Sid >)
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

### 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.

* Provide the new version upgrade documentation/FAQ.

* Make the sentence more clear.

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

* mvnw proxy config

explanation about config proxy mvnw
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

* Add lombok dependency into root pom.xml

* Update all depending lombok pom.xml(s)

* Change lombok version into latest(1.18.10)

* Revert lombok dependency config of test projects

* Remove redundant lombok dependency of submodule

* Move Lombok into dependencies node for applying globally

### Motivation:

Codes clean up

### Modifications:

- Remove v1 header, follow up #4244

- Use built-in Base64 class (since JDK8)

### Result:

- No more legacy v1 headers

- No unnecessary codes concerns by using built-in ability

### Motivation:

Make E2E tests more stable.

### Modifications:

Verify the traces loosely as other tests, and remove the `verify` method which verifies traces strictly, as we have preparation that also generates traces.

### Result:

E2E tests are more stable.

Motivation:

Reduce unnecessary memory allocation in frequently used class.

Modifications:

Replace the `AtomicInteger` with `AtomicIntegerFieldUpdater`

Result:

We can save 4 bytes (for the reference to `AtomicInteger` itself) for each `TracingContext`, which saves credible memory in a high-concurrent agent service.

* provide profile analyze empty interfaces

* fix comment error

* change comments

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

* Enhance gRPC plugin
Co-authored-by: NKanro <higan@live.cn>
Co-authored-by: Nkezhenxu94 <kezhenxu94@163.com>
Co-authored-by: NGuoDuanLZ <739537111@qq.com>
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

* Provide Avro plugin
* provide testcase for avro-plugin
Co-authored-by: Nkezhenxu94 <kezhenxu94@163.com>

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

* add exclude licene file dir.

* update comment.

* update pom exclude dir.

* update comment.
Co-authored-by: Nkezhenxu94 <kezhenxu94@163.com>
Co-authored-by: 吴晟 Wu Sheng <wu.sheng@foxmail.com>

* merge e2e profile test project, Use `env` to distinguish different storage types

* remove maven child module

* change `env` -> `storage`
Co-authored-by: Nkezhenxu94 <kezhenxu94@163.com>