Why should the first letter of a Java class be upper-cased? [closed]

Question

Why should the first letter of a Java class be upper-cased? Is it not possible to run a program containing lower-cased class names? If it is possible, what's the difference?

Answer 1

It's a coding convention, adopted by most Java programs. It makes reading code easier as you become use to a given standard.

No, you don't have to follow it, but you won't make any friends by not doing so ;)

Why / how was this convention established in the first place?

The convention was established by Sun/The creators of the Java language.

It was likely establish to improve the promotion of the language across a wide and diverse audience, to lower the entry level requirements for new developers (much easier to learn if you don't need to keep switching between other people's "ideas" of what good code looks like) and generally to try and keep the code clean within the community.

You could ask "why do companies have style guidelines for coders?" and the reasons would, generally, be the same

Answer 2

Using naming conventions makes it easier to quickly understand code when you read it.

Here are two simple lines of code:

foo = FooFactory.getFooInstance();
foo.doSomethingFoosDo();

If we know the author follows naming conventions, we quickly know several things:

1. foo is an instance of some class
2. FooFactory is a class
3. getFooInstance() is a static method of the class FooFactory
4. doSomethingFoosDo() is an instance method of foo

Otherwise we waste time wondering things like "is FooFactory an object or a class?"

Without naming conventions, you'd actually have to search through the source code to answer such questions.

This seems overly uptight at first, but it makes an ENORMOUS difference as you begin to write more complex software and work with others.

You'll find that naming conventions even make your own code more readable.