Java Class declaration

[vermio]

Hi,
I'm a very beginner in java and I don't want to have questions, that's why I'm asking:
One class can be declared as static or private or nothing.
If you don't declare it as public or private (eg. class myclass {...})
what type is it?
And why in an example program that I have, the compiler complains if I declare it as public or private but it's ok if I don't put anything in front of its name?:)

[Eranga]

Then the class have default access. Any class, field (variable), method or constructor that has no declared access modifier is accessible only by classes in the same package, not from the different packages. The default modifier is not used for fields and methods within an interface. If you can go to the Suns' tutorial, you can find a lot about those access modifiers.

[Eranga]

Read the following page. Hope you can have a basic idea about those access modifiers in Java.

[vermio]

Thanks for the reply.

I have the following simple program:
class testClass {
public static void main(String[] args) { int i = 1; }
}

I compile it and it's ok.
If I make the class public or private I have (different) compilation errors.
I can understand these kind of errors but it's obvious that java doesn't treat to the class neither as private nor as public.

Eranga, what following page do you mean?

[Tolls]

You shouldn't get any compilation errors for setting that class public.

[tim]

Hi vermio

You can only have a single public class in a java source file.

public class Main {
	public static void main(String[] args) {
		int i = 1; 
	}
}

Compiles fine.

public class Main {
	public static void main(String[] args) {
		int i = 1; 
	}
}

public class Oops {

}

Doesn't compile and gives an error:

...\Main.java:7: class Oops is public, should be declared in a [COLOR="RoyalBlue"]file named Oops.java[/COLOR]
public class Oops {
       ^
1 error

If you have a different error, please post the error message.

Thanks
Tim

[vermio]

FileName: pr01.java

Public class testClass {
public static void main(String[] args) { int i = 1; }
}
pr01.java:1: class testclass is public, should be declared in a file named testClass.java

Understood

Private class testClass {
public static void main(String[] args) { int i = 1; }
}
pr01.java:1: modifier private is not allowed here
Understood

class testClass {
public static void main(String[] args) { int i = 1; }
}
No errors

I think it's because it is considered as a package? Am I right?
(I haven't studied about packages yet).

[Tolls]

Well, it all stems from the filename being different.

You can have as many non-public classes defined in a java file as you want. They will only be visible to other classes in that package. It is not to do with it considering the class a package.

You can only have one public class defined (ignoring inner classes here), and no private classes.

[al_Marshy_1981]

FileName: pr01.java

[I]Public class testClass
[I]Private class testClass {

public uses a small 'p' not a capital 'P' same goes for private....

[Eranga]

Eranga, what following page do you mean?

Sorry I've misses that.

Controlling Access to Members of a Class (The Java™ Tutorials > Learning the Java Language > Classes and Objects)

[Hema26]

if you done specify access modifier then class is package public means that class is accessible withing the package. where as public class is accessible outside the package also.
i hope i have cleared ur doubt.
Hema26

[Hema26]

hi
if u declare the class public then u must save ur program with same name you have given to ur class. e.g
if u have declared a class Student as public then u must save ur program with same name i.e. Student otherwise it will give error.
regards
Hema26

[Tolls]

Txt spk is n abmntn.

[vermio]

thank u all guys.

[Eranga]

If you've solve the problem please mark the thread solved.

[vermio]

Eranga,
sorry, but how can I do this?

[Eranga]

On top of the thread you can see a menu. Click on thread tools, and on the drop down menu list you can find an option to mark the thread solved.

[Lil_Aziz1]

If a class doesn't have a modifier, what implicit modifier does it have?

//ERROR
public class SomeStuff {

}
public class NotSomestuff {
	
}

//ERROR
public class SomeStuff {

}
private class NotSomestuff {
	
}

//ERROR
public class SomeStuff {

}
protected class NotSomestuff {
	
}

Thus, the implicit modifier can't be public, private, or protected. What's left? abstract and final? Those are irrelevant in this case aren't they?

The question is, what implicit modifier does a class have if no modifier is identified?

[Tolls]

It's package protected (or whatever the offical term is).
That is, only things in the same package can access it.
I originally thought you could have protected, but you're right, that's not the case.

[Singing Boyo]

package private is the proper term :) package protected would infer that sub-packages can access it, and I'm quite sure that isn't the case.

As for why your getting errors, your class is named testClass, and the file is pr01.java. The file should be testClass.java, or the class should be named pr01. (I think you got that, but just to be sure...)