What characters can a variable name consist of (a valid identifier) in Java

The name or identifier of a variable is a sequence of lowercase and uppercase Latin letters, numbers, as well as the symbols "$" and "_". A variable name can start with any of the listed characters, except a number.

It is technically possible to start a variable name with "$" or "_" as well, but this is prohibited by the Java Code Conventions. Also, the dollar symbol "$" is never used at all by convention. By convention, a variable name must begin with a lowercase letter (class names begin with a capital letter). Spaces are not allowed when naming variables.

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