Re: Newbie query regarding Java
"Matt Rose" <matt.rose.at@gmail.com> wrote in message
news:1170947618.263937.275460@j27g2000cwj.googlegroups.com...
(Aside.) Whether the convention of having a method with a magic
signature as the entry point into all standalone java programs is
better than some more explicit approach like an Interface might be
worth wondering about. It made the original sales case for java closer
to C I suppose. I expect other people can come up with better
arguments either way.
From my perspective, it's not that method which has a magic signature:
the evidence is that you can have multiple class each with their own "public
void static main(String[])" methods, and none of them are any more magical
than any other. Rather, it's the behaviour of the JVM itself which is
"magical". It can somehow manage the transfer of control from the command
line (or other external environment) into the JVM.
It just so happens that the "java.exe" command happens to take a class
as a command line argument, and tries to invoke the static main(String[])
method of that class. But this is not conceptually different from a browser
creating an instance of a JApplet, and invoking its init(), start() and
stop() and destroy() methods. Doesn't mean that the JApplet is magical. It
just means that there's some sort of transfer of control from your program
to the outside environment.
I believe there are even IDEs for which you can specify the entry point
to be something other than a method called "main" (e.g. a static method
called "foo(String[])" instead), which further reinforces that the magic
lies not in the method, but somewhere at a higher level than that.
- Oliver