Re: RFR: JDK-8245432: Lookup::defineHiddenClass should throw UnsupportedClassVersionError if the given bytes are of an unsupported major or minor version

[Alan Bateman]

On 28/05/2020 18:25, Mandy Chung wrote:

:

The runtime will ensure if --enable-preview is set if a class file with minor is loaded.   I will prefer to keep VM::isSupportedClassFileVersion to validate the given major/minor version.  At runtime, it will fail when such class file is loaded if preview is not enabled.

I'll add a comment to describe that.

Will readUnsignedShort throw AIOBE if the offset is beyond the length?

Good catch.  I add the check to throw CFE.

+            private static int readUnsignedShort(byte[] bytes, int offset) {

+                if (offset >= bytes.length) {

+                    throw new ClassFormatError("Invalid ClassFile structure");

+                }

+                return ((bytes[offset] & 0xFF) << 8) | (bytes[offset + 1] & 0xFF);

+            }

Also are you sure about "& 0xCAFEBABE", I assumed it would just check the magic number is equal to that.

It should check ==.  Fixed.

Thanks, this is okay with me.

-Alan.