The body of an interface may declare members of the interface:
InterfaceBody:
{
InterfaceMemberDeclarationsopt}
InterfaceMemberDeclarations:
InterfaceMemberDeclaration
InterfaceMemberDeclarationsInterfaceMemberDeclaration InterfaceMemberDeclaration:
ConstantDeclaration
AbstractMethodDeclaration
The scope of the name of a member declared in an interface type is the entire body of the interface type declaration.