Java Reference
In-Depth Information
That's the whole program. In Java, you need a
main
method inside a class, and inside the
main
method you call
System.out.println
to write to the console. Java developers
are used to it, but there are roughly 8 to 10 different object-oriented concepts involved, de-
3
A rough count includes classes, methods, strings, arrays, public access, static methods and attributes, void return
types, overloaded methods like
println
, and more. It's no accident that Bruce Eckel's
Thinking in Java
(Prentice-
Hall, 2002) takes over 100 pages just to get to his first “Hello, World” program.
To demonstrate, consider one of the two execution environments that come with Groovy,
that allows you to execute Groovy code a line at a time. All of the lines in the following
listing produce the same result.
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Read-Eval-Print Loop; see
http://en.wikipedia.org/wiki/REPL
for details.
Listing B.1. Running “Hello, World!” in the Groovy shell