2 classes in one file. Is that possible?

[Stee Munche]

Well I wanted to know if I can put two different classes in one file?
If that's possible how do I name the file???

[Paul Sturrock]

Absolutely. The Java spec. only limits you to one public type declaration in a file (and that file's name must match the type), but this is perfectly doable:

public class Foo {
}
 
class Bar {
 
}
 
class Whatever {
 
}

[ February 22, 2006: Message edited by: Paul Sturrock ]

[Jeff Albertson]

That being said, most people divide code into one top-level class per file. Are you just asking or do you want to place more than one in a file? If so, why?

[Stee Munche]

Well it's just for the sake of knowing. I know that if there is only one class called Foo, therefore we have to name the file Foo.java. So I wanted to know if putting two or more classes in one file is possible and how should I name the file as I know that if a file contain only one class, eg class Foo therefore if I name the file Too.java, there will be an error.
So how should I name the class with multiple classes??? With the one that's gonna use the other classes???

[Keith Lynn]

As said before you can have as many top-level classes in a source file as you want, but only one that's declared public. The name of the file must match exactly the name of the public class. Remember that Java is case-sensitive.

[Stee Munche]

Sorry for repeating the question.
Paul already gave the answer but when reading the first time I think that I didn't read between the parenthesis, was more focuses on the codes he gave.

[Tony Morris]

Just for clarification, one public *top-level* type declaration in a file.
This compiles fine:

public class X {
    public class Y {
 
    }
}

[Jean Fore]

Tony, that's an inner class right?
Thanks
-Jean

[Tony Morris]

Originally posted by Jean Fore:
Tony, that's an inner class right?
Thanks
-Jean

Yes, it is an inner class - a special type of nested class.
All classes are either nested or top-level.
So the statement that "one top-level public type per source file" can be accurately translated to "one non-nested public type per source file".

There are other types of nested classes (that are not inner classes) that can be public within a public declaration.

http://jqa.tmorris.net/GetQAndA.action?qids=67&showAnswers=true