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file.toUpperCase()
Does the File class have a method with that name? The compiler doesn't think it does.

new StringBuilder(file)
Does the StringBuilder class have a constructor that takes a...

The full text of the message has useful info. Your edited version leaves stuff out.

What don't you understand about: cannot find?

Does the File class have a method by that name?
Is there a...

Can you give us your errors or question?
Please copy and paste here the full text of the error messages.