private static boolean functionalInterfaceReturnsExactlyVoid ( Type interfaceType , VisitorState state ) { return state . getTypes ( ) . findDescriptorType ( interfaceType ) . getReturnType ( ) . getKind ( ) == TypeKind . VOID ; }
Checks that the return value of a functional interface is void . Note we do not use ASTHelpers . isVoidType here return values of Void are actually type - checked . Only void - returning functions silently ignore return values of any type .