Indy plugins

[felixbarny]

Uses Byte Buddy's new ability to dispatch to advices via INVOKEDYNAMIC.

Excerpt from the Javadoc of IndyBootstrap:

  Bootstrap CL ←──────────────────────────── Agent CL
      ↑ └java.lang.IndyBootstrapDispatcher ─ ↑ ─→ └ {@link IndyBootstrap#bootstrap}
    Ext/Platform CL               ↑          │       ╷
      ↑                           ╷          │       ↓
    System CL                     ╷          │ {@link HelperClassManager.ForIndyPlugin#getOrCreatePluginClassLoader}
      ↑                           ╷          │       ╷
    Common               linking of CallSite │       ╷
    ↑    ↑             (on first invocation) │    creates
WebApp1  WebApp2                  ╷          │       ╷
         ↑ - InstrumentedClass    ╷          │       ╷
         │                ╷       ╷          │       ╷
         │                INVOKEDYNAMIC      │       ↓
         └────────────────┼──────────────────Plugin CL
                          └╶╶╶╶╶╶╶╶╶╶╶╶╶╶╶╶→ ├ AdviceClass
                                             └ AdviceHelper
Legend:
 ╶╶→ method calls
 ──→ class loader parent/child relationships

First step of #1085
Supersedes #1090

Refactors the JDBC and Servlet plugin to be indy plugins. Prepares some more plugins for easy migration to indy plugins.

[apmmachine]

💚 Build Succeeded

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Build stats

• Build Cause: [Pull request #1230 updated]

• Start Time: 2020-07-01T10:05:09.990+0000

• Duration: 43 min 29 sec

Test stats 🧪

Test	Results
Failed	0
Passed	556
Skipped	11
Total	567

[SylvainJuge]

As said during the meeting we had today:

• we might slightly improve @AssignTo* annotations by using nested annotations in a similar way as @Advice.Return or @Advice.Local with that we could have : @AssignTo.ReturnValue, @AssignTo.Parameter and so on.
• Finding a way to use named keys to bind to method parameters (instead of confusing index and value), could also be a good improvement. For example annotating an advice parameter with @AssignTo.Key("value") could allow to then refer to it by name (rather than index) in @AdviceTo annotation.

[eyalkoren]

Epic PR!! That's really a whole new agent technology!

First review chunk - looks great so far, didn't find anything major, a few minor comments/suggestions/questions.

[eyalkoren]

Chunk 2, a smaller one today...

[eyalkoren]

LGTM.
Did we get to a threshold of doing more non-inlined than inlined? If so, can and should we configure BB to not-inline by default and explicitly define only when we want to inline?

[eyalkoren]

Maybe even more explicit is:

Suggested change

	assertThat(Stream.of("foo", "bar", "baz")
	.parallel()
	.<AbstractSpan<?>>map(s -> tracer.getActive())
	.distinct())
	.containsExactly(transaction);
	assertThat(Stream.of("foo", "bar", "baz")
	.parallel()
	.<AbstractSpan<?>>map(s -> tracer.getActive()))
	.containsExactly(transaction, transaction, transaction);

[felixbarny]

True, but I don't want to execute the tests again because of that.