Make some of the Java classes in module-http proper utility classes

[vil02]

Description:

Some of the Java classes in http module, namely:

• Http2Util,
• TestUtil,
• MessageGenerator,
• WebSocketTestConstants,
• Continue100Util,
• ProxyServerUtil,
• TestUtils,
• Http2StateUtil,
• LogLevelMapper,
• ExternRequestContext,
• ExternUtils,
• DispatcherUtil,
• Constants,
• Constants,
• HttpCompilerPluginUtil,
• Constants,
• HttpInterceptorResourceValidator,
• HttpResourceValidator,
• AbstractLSCompilerPluginTest - this cannot be a proper utility (cf. AbstractCompletionTest or AbstractCodeActionTest),
• CompilerPluginTestConstants,
• TestConstant,
• ExternRetryMultipartTestutil,
• Assert,
• Utils,
• HttpUrlClient,
• ExternPipeliningTestUtil,

appear to be utility classes (i.e. all of the members and methods are static). Generally speaking it is a good practice to:

• explicitly mark their default constructor as private (like in ModuleUtils) - because it does not make sense to have objects of such classes,
• mark such classes as final - because it does not make sense to derive any class from them.

There are benefits of doing this:

• the design is cleaner - e.g. no one will create objects of such classes,
• the coverage report will show higher/more accurate coverage (currently it is complying that instantiation of these classes is not tested).

Suggested Labels:

module/http,hacktoberfest

Suggested Assignees:

@vil02

Affected Product Version:

OS, DB, other environment details and versions:

Steps to reproduce:

Related Issues:

#4894, #4901, #4902, #4910, #4911, #4918, #4919, #4921.