Fix class annotations on JDK17 and newer

[Uthar]

JDK 17 Removed some obsolete class file format in regards to runtime visible annotations.

Now, the annotation parser requires a class type signature, i.e. has stopped accepting a class, in the constant pool.

See the JDK commit "Remove vestiages of intermediate JSR 175 annotation format" (https://github.com/openjdk/jdk/commit/8758b554#diff-50de65a27d09a727c0b6ea40ce7ebd97bf7ead098ff910d7757ae0dd781fc2c8R240)

fix #473