Java Programming/Keywords/class

class is a Java keyword which begins the declaration and definition of a class.

The general syntax of a class declaration, using Extended Backus-Naur Form, is

class-declaration ::= [access-modifiers ] class  identifier 
 [extends-clause] [implements-clause] 
 class-body
extends-clause ::= extends  class-name
implements-clause ::= implements  interface-names 
interface-names ::= interface-name [, interface-names]
class-body ::= { [member-declarations] }
member-declarations = member-declaration [member-declarations]
member-declaration = field-declaration 
 | initializer 
 | constructor 
 | method-declaration
 | class-declaration

The extends word is optional. If omitted, the class extends the Object class, as all Java classes inherit from it.