Thread: java

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on execution of this program it shows me an error as " class locc1 is public, should be declared in a file named locc1.java .

That pretty much says it all. A public class in a file must be within a file of the same name. Name you file as it suggests.

Originally Posted by vignesh gopalakrishnan

...want the reason why...

There are some rules that Java application programmers must live with.

Here are some that are related to your problem, and may cover other questions that might arise early in your development.

1. For projects consisting of one file, the file must have a public class. It can have other classes, but it can only have one public class. The file name must consist of the class name and a .java extension.
   
   
2. Execution will start in a main function of a public class. The main() function must be declared public static void, and it must have exactly one argument, which is String array.
   
   
3. A program can consist of material from many files. Other files can have other classes (and certain other Java constructs). Other files can have public classes. Each file can have at most one public class. If any file has a public class, the name of that file must consist of the class name and a .java extension.
   
   
4. Of all of the files and all of the classes in a given project, only one public class can have a static void main function that has a single String array argument.

These notes apply to Java application programs. Other types of Java programs may have somewhat different rules to live by. (Java Applets won't have a main function, for example.)

Cheers!


Z

Clarifying to Zaphod's post above:
1. Projects can have multiple public classes (even classes can have multiple public inner classes)
3. Same dodgy language as #1, files can contain more than one public class.
4. There can be multiple classes in a project with a main, however the JVM will only execute the main specified upon execution (this can be specified either in the IDE at runtime or in the manifest of an executable jar file)

Originally Posted by aussiemcgr

Clarifying to Zaphod's post above:...)

Thank you for the clarification. Well, more than clarification. Thank you for the corrections.

I'm kind of new to Java, and I "discovered" several things without reading entire books and reference manuals. I wanted to share my fresh learning experiences, and I'm sure the "rules" can be stated more precisely (and correctly).

I will say that if I create a file with more than one public class I get a javac compiler error, and that's why I put that as part of items 1 and 2. I wasn't thinking of inner public classes.

Maybe my list of "rules" should have been titled "Things to help you get started until you have had the time and the motivation and the stamina to read all 684 pages of Version 3 of the Java Language Specification."

Now, getting a head start on my Winter Sports Encyclopaedia (to be published Real Soon Now), I am starting a list of "Important Rules for Beginning Skiiers."

1. Don't eat yellow snow.

Cheers!

Z