classes

[manohar reddy]

Can we write multiple classes in a single .java file?

If yes then, can all of them be public classes

If we have multiple classes in one .java file, what should be the name of the java file?

[Ben Souther]

manohar reddy,

These sound a lot like homework questions to me.
Are they?

Why don't you start by telling us what you think the answers are?
Have you tried to find this out by writing several classes in a single Java file? If so, what happened?

[Olivier Legat]

Yes, you can. However you can only have one "main" method. The file must have the same name as the class that holds the "main" method.

[Joanne Neal]

Originally posted by Olivier Legat:
Yes, you can. However you can only have one "main" method. The file must have the same name as the class that holds the "main" method.

Actually all the classes can have a main method. Which one will be executed depends on your command line.

Try this (all in one file called MainTest.java)

package test;
 
public class MainTest
{
public MainTest()
{
        System.out.println("This is public MainTest");
}
 
public static void main(String[] args)
{
MainTest maintest = new MainTest();
}
}
 
class MainTest1
{
    public MainTest1()
    {
        System.out.println("This is MainTest 1");
    }
 
    public static void main(String[] args)
    {
        MainTest1 maintest = new MainTest1();
    }
}

Compile it and then run the following commands

java -cp . test.MainTest
java -cp . test.MainTest1