When i used notepad++ to write the code below, I compiled it in command prompt and got the following error message.I wonder why it is running in Net beans . The error message. Exception in thread "main" java.lang.NoClassDefFoundError ifThenElse <wrong name: ifThenElse/ifThenElse> .It had some package extensions below.
I think what you are missing is the correspondence between directories and package names. The package name in your class is ifThenElse, and the class name is ifThenElse. Therefore, you need to have this relative file path: ./ifThenElse/ifThenElse.class.
Let's assume you are on Windows and the source file is located here:
You need to have a command prompt open at c:\mySimpleApp. In that command prompt you can enter:
When using an IDE like Netbeans or Eclipse, it usually handles all of this package/folder correspondence for you. But knowing how to do this using a simple editor such as Notepad++ and doing everything from the command line is a good way to learn subtle points like this about Java.
Finally, by convention, class names usually start with initial caps.