Disallowing the dynamic loading of agents by default (revised)

[mark.reinhold at oracle.com]

2017/4/6 2:07:27 -0700, michael.rasmussen at zeroturnaround.com:
> On 6 April 2017 at 02:34,  <mark.reinhold at oracle.com> wrote:
>> Interesting.  Perhaps we need a `Self-Premain-Class` attribute, or some
>> such.
>> 
>> Out of curiosity, would it do any harm in your `java -jar` case if the
>> agent is activated?
> 
> As it is right now, yes, that would cause the execution to potentially fail.
> Should a Self-Premain-Class (or like) not be implements, we would have
> to check in the beginning of premain if we are running in java -jar
> mode, and if such, make premain a no-op.

Okay, so how about this revised proposal:

  - Define a new JAR-file manifest attribute, `Launcher-Agent-Class`.
    If this attribute is present in the manifest of an executable JAR
    file then the `agentmain` method of the specified class will be
    invoked prior to invoking the `main` method of the application.
    The JAR file will, effectively, be loaded also as a dynamic agent.

    This will allow `java -jar foo.jar` to be used in place of the more
    verbose `java -javaagent:foo.jar -jar foo.jar`.

- Mark