The {@code target} and {@code cleanup} must have the same corresponding argument and return types, except that {@code cleanup} may omit trailing arguments.

BUT

1. IllegalArgumentException: bad spread array length
WHEN
private static void target(int a1, long a2, Object a3, int b1, long b2, Object b3) {}
private static void cleanup(Throwable t) {}

2. WrongMethodTypeException: cannot convert MethodHandle(Throwable,int,long,Object[])void to (Throwable,Object[])void
WHEN
private static void target(int a1, long a2, Object a3, int b1, long b2, Object b3) {}
private static void cleanup(Throwable t, int a1, long a2, Object a3, int b1) {}