Interfaces - The Java Language Specification - page 268

If two or more (distinct) interface modifiers appear in an interface declaration, then
it is customary, though not required, that they appear in the order consistent with that
shown above in the production for InterfaceModifier .
9.1.1.1. abstract Interfaces
Every interface is implicitly abstract .
This modifier is obsolete and should not be used in new programs.
9.1.1.2. strictfp Interfaces
The effect of the strictfp modifier is to make all float or double expressions within the interface
declaration be explicitly FP-strict (§ 15.4 ) .
This implies that all nested types declared in the interface are implicitly strictfp .
9.1.2. Generic Interfaces and Type Parameters
An interface is generic if it declares one or more type variables (§ 4.4 ) .
These type variables are known as the type parameters of the interface. The type parameter
section follows the interface name and is delimited by angle brackets.
In an interface's type parameter section, a type variable T directly depends on a type vari-
able S if S is the bound of T , while T depends on S if either T directly depends on S or T
directly depends on a type variable U that depends on S (using this definition recursively).
It is a compile-time error if a type variable in a interface's type parameter section depends
on itself.
The scope of an interface's type parameter is specified in § 6.3 .
It is a compile-time error to refer to a type parameter of an interface I anywhere in the de-
claration of a field or type member of I .
A generic interface declaration defines a set of parameterized types (§ 4.5 ) , one for each
possible invocation of the type parameter section by type arguments. All of these paramet-
erized types share the same interface at run time.
9.1.3. Superinterfaces and Subinterfaces
If an extends clause is provided, then the interface being declared extends each of the other
named interfaces and therefore inherits the member types, methods, and constants of each
of the other named interfaces.