valid identifier

newState

is this a valid identifier? because it contains new

it is. but if you leave space between new State then it is not.

It is valid. myClass is valid, myStaticBoots is valid, myAbstractDog is valid. newYork is also valid

As long as the given name is not a reserved keyword.

Why don't you write a small program with a variable named "newState", try to compile it and see what the compiler says?

you mean to say that newState is valid because it is not a keyword, even if new is keyword and it is part of identifier?

and one more thing guys, how do you identify whether ti use lowercase or uppercase letters when declaring variables?

Names are usually consisting of word, whose first letter is upper-case.
Like "isRainFalling", "carColour", "dayOfMonth"....

is carcolor and Carcolor valid?

Both "Carcolor" and "carcolor" will get past the compiler as valid identifiers, but (as you already know) they don't match the coding conventions for people who have to read the code.

you mean to say it is a set standard?

not a strict rule or error?

thank you so much.

i am learning so much from here

You can check some common naming conventions here :
http://java.sun.com/docs/codeconv/html/CodeConventions.doc8.html#367

Note that this is mandatory, but it really helps to make your code clean and readable to others.