Sun's JDK raises VerifyError when an interface contains <clinit> without a code attribute.
JVMS, 2nd Edition, Chapter 4.6 Methods states:
Class and interface initialization methods (3.9) are called implicitly by
the Java virtual machine; the value of their access_flags item is ignored
except for the settings of the ACC_STRICT flag.
Thus, ClassFormatError should be thrown in such case, because:
- the value of ACC_ABSTRACT is among the ignored flag (as others but except ACC_STRICT)
- ACC_ABSTRACT cannot be used to suggest that VM should not check for a Code attribute
- the unstated implicit assumption is that if <clinit> exists, it must have a Code Attribute
- the check for the existence of a Code Attribute should result to ClassFormatError,
not a VerifyError.
It is fine for other methods that ACC_ABSTRACT implies no code attribute,
but <clinit> is specifically excepted by the above paragraph.
Note that Sun's JDK raises VerifyError in such cases at least since JDK 1.2.
Please see comments for 6300312 for more details.