vmspec-4.1.md

JVM Specification 4

4.1 The Classfile Structure

http://docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html#jvms-4.1

Table 4.1. Class access and property modifiers (abbreviated)

• ACC_PUBLIC
• ACC_FINAL
• ACC_SUPER
• ACC_INTERFACE
• ACC_ABSTRACT
• ACC_SYNTHETIC
• ACC_ANNOTATION
• ACC_ENUM

…

If the ACC_INTERFACE flag of this class file is set, its ACC_ABSTRACT flag must also be set (JLS §9.1.1.1). Such a class file must not have its ACC_FINAL, ACC_SUPER or ACC_ENUM flags set.

An annotation type must have its ACC_ANNOTATION flag set. If the ACC_ANNOTATION flag is set, the ACC_INTERFACE flag must be set as well. If the ACC_INTERFACE flag of this class file is not set, it may have any of the other flags in Table 4.1 set, except the ACC_ANNOTATION flag. However, such a class file cannot have both its ACC_FINAL and ACC_ABSTRACT flags set (JLS §8.1.1.2).

…

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1. ACC_ANNOTATION -> ACC_INTERFACE

2. "If the ACC_INTERFACE flag of this class file is not set…" Which class?

   1. The one with ACC_ANNOTATION -> See rule 1.

   2. Some arbitrary class -> "may have any … other flags … set, except the ACC_ANNOTATION … However, … cannot have both its ACC_FINAL and ACC_ABSTRACT flags set"

Contradiction?