The Java® Language Specification, Java SE 7 Edition, Fourth Edition

9.1. Interface Declarations

An interface declaration specifies a new named reference type. There are two kinds of interface declarations - normal interface declarations and annotation type declarations (§9.6).

InterfaceDeclaration:    NormalInterfaceDeclaration    AnnotationTypeDeclarationNormalInterfaceDeclaration:    InterfaceModifiers_opt interface Identifier    TypeParameters_opt ExtendsInterfaces_opt InterfaceBody

The Identifier in an interface declaration specifies the name of the interface.

It is a compile-time error if an interface has the same simple name as any of its enclosing classes or interfaces.

The scope and shadowing of an interface declaration is specified in §6.3 and §6.4.

9.1.1. Interface Modifiers

An interface declaration may ...