Classes - The Java Language Specification - page 216

The last formal parameter of a method or constructor is special: it may be a variable arity
parameter , indicated by an ellipsis following the type.
If the last formal parameter is a variable arity parameter, the method is a variable arity
method . Otherwise, it is a fixed arity method .
If a method or constructor has no formal parameters, only an empty pair of parentheses ap-
pears in the declaration of the method or constructor.
FormalParameterList:
LastFormalParameter
FormalParameters , LastFormalParameter
FormalParameters:
FormalParameter
FormalParameters , FormalParameter
FormalParameter:
VariableModifiers opt Type VariableDeclaratorId
VariableModifiers:
VariableModifier
VariableModifiers VariableModifier
VariableModifier: one of
Annotation final
LastFormalParameter:
VariableModifiers opt Type ... VariableDeclaratorId
FormalParameter
The following is repeated from § 8.3 to make the presentation here clearer:
VariableDeclaratorId:
Identifier
VariableDeclaratorId [ ]
If an annotation a (§ 9.7 ) on a formal parameter corresponds to an annotation type T (§ 9.6 ) ,
and T has a (meta-)annotation m that corresponds to java.lang.annotation.Target , then m must
have an element whose value is java.lang.annotation.ElementType.PARAMETER , or a compile-
time error occurs.
The scope and shadowing of a formal parameter is specified in § 6.3 and § 6.4 .
It is a compile-time error for a method or constructor to declare two formal parameters with
the same name. (That is, their declarations mention the same Identifier .)