Found by Zoltan Majo:

$ java -jar jol-cli/target/jol-internals.jar java.lang.Class
Running 64-bit HotSpot VM.
Using compressed references with 3-bit shift.
Objects are 8 bytes aligned.
Field sizes by type: 4, 1, 1, 2, 2, 4, 4, 8, 8 [bytes]
Array element sizes: 4, 1, 1, 2, 2, 4, 4, 8, 8 [bytes]

VM fails to invoke the default constructor, falling back to class-only introspection.

java.lang.SecurityException: Cannot make java.lang.Class.classLoader accessible
        at java.lang.reflect.AccessibleObject.setAccessible0(AccessibleObject.java:147)
        at java.lang.reflect.AccessibleObject.setAccessible(AccessibleObject.java:129)
        at org.openjdk.jol.info.FieldData.computeOffset(FieldData.java:76)
        at org.openjdk.jol.info.FieldData.parse(FieldData.java:58)
        at org.openjdk.jol.info.ClassData.parseClass(ClassData.java:87)
        at org.openjdk.jol.info.ClassLayout.parseClass(ClassLayout.java:59)
        at org.openjdk.jol.info.ClassLayout.parseClass(ClassLayout.java:48)
        at org.openjdk.jol.MainObjectInternals.main(MainObjectInternals.java:53)