Java™ How To Program (Early Objects), Tenth Edition

Class Names and Identifiers

By convention, class names begin with a capital letter and capitalize the first letter of each word they include (e.g., SampleClassName). A class name is an identifier—a series of characters consisting of letters, digits, underscores (_) and dollar signs ($) that does not begin with a digit and does not contain spaces. Some valid identifiers are Welcome1, $value, _value, m_inputField1 and button7. The name 7button is not a valid identifier because it begins with a digit, and the name input field is not a valid identifier because it contains a space. Normally, an identifier that does not begin with a capital letter is not a class name. Java is case sensitive—uppercase and lowercase letters are distinct—so value and ...