The following code in sun/jvm/hotspot/tools/jcore/ClassWriter.java tries to skip the overpass methods

https://github.com/openjdk/jdk/blob/a8871f5d26e5cb42c031c7b736ec30b1b147a2bc/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/tools/jcore/ClassWriter.java#L436-L446

       for (int i = 0; i < methods.length(); i++) {
            Method m = methods.at(i);
            long accessFlags = m.getAccessFlags();
            // overpass method
            if (accessFlags == (JVM_ACC_PUBLIC | JVM_ACC_SYNTHETIC | JVM_ACC_BRIDGE)) {
                continue;
            }

However, accessFlags may contain bits that are internal to the JVM. They should be masked off using:

long accessFlags = m.getAccessFlags() & JVM_RECOGNIZED_METHOD_MODIFIERS;