basic java doubt ? access specifier ?

SUNIL GUTTA

13y2.7kJava

Hi

HERE is mu program .. it works fine no problem with that .. but it only compiles when i remove public specifier from the class " Horsetest" .. why is this happening ?? any ideas .. in c# if we declare like this program will execute no compile error .. why

Program :
public class HorseTest
{
public static void main (String [] args)
{
class Horse
{
public String name;
public Horse(String s)
{
name = s;
}
}
Object obj = new Horse("Zippo");
Horse h = (Horse) obj;
System.out.println(h.name);
}
}

please help me :) cheers

11 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes13y ago
Accepted answer
It depends what you're calling the file.

If you're calling it HorseTest.java, then it should compile whether the HorseTest class is public or not.

However, if you're calling it something else (Horse.java perhaps), then it won't compile if the HorseTest class is public - no problem otherwise.

The reason is that, if you have a public class, then the file name should be the same as that class (plus .java). If you don't have a public class, then you can call the file what you want.
SUNIL GUTTA13y ago
Humm ty have a nice day .. got clarity :) cheers
Vulpes13y ago
You're correct that there's no limitation on file names in C# whether they contain public classes or not. They don't even need a .cs extension!
SUNIL GUTTA13y ago
well ty mate for your time for KT . . you just blown me away with ur awesome explanation :)

One final question in this post ..

Well you said when we keep the file name same as class name (which is fallowed in Real time)
in java the clas can be made as public right ,,

What if i made a c# code file with class public and different file name .. but still it is executing perfectly ?? any reason or am i wrong . .

cheers & ty for ur continued help
Vulpes13y ago
Yeah, it looks like the file is always named Main.java if you use a public class - hence the error.

So, when you use that site to compile your Java source code, I'd avoid using public classes.

SUNIL GUTTA13y ago

Main.java:8: error: class HorseTest is public, should be declared in a file named HorseTest.java public class HorseTest 

The site link i used is : http://ideone.com

Vulpes13y ago
If you're using an online compiler, then you may not have any control over what the file is called as they might use a system which ensures that file names are unique.

Certainly, my desktop Java compiler isn't bothered whether the main class is public or not as long as the file name and class name are the same.

What error message do you get?
SUNIL GUTTA13y ago
TY TY soo much u cleared mine doubt completely .. .. ..

but small thing .. when i tried to compile online .. its showing compile error when keeping public to class ..

why is it ..
Vulpes13y ago
The class which includes the main() method doesn't have to be public but, if it is, then the file must have the same name as the public class.

Even if the 'main class' isn't public, it's still considered good practice to give the file the same name as the class.

Although I'm not keen on the practice personally, it's not uncommon to nest classes within other classes even in C#.

However, one thing you can do in Java but not (thankfully) in C# is to nest a class within a method as you did in your example.

Java has packages rather than namespaces which fulfil the role of avoiding name collisions and some other things besides.
SUNIL GUTTA13y ago
Well dude ..
java program is bit confusing compared to c# ..

In c# we rarely declare a class in side a class right ?

what were these name spaces in c# called in java ?? does they exist ?

TY
SUNIL GUTTA13y ago
so well i got you nearly ..

So public to the above code is nothing to do with main method ..

My friend said if a class contains a main method in it it is called main class .. then the main class should'nt be public must he said ?? ..
is he right ..

Thank you