Mention Byte Buddy in the documentation additionally to cglib and increase versions

Author: Vampire

docs/interaction_based_testing.adoc

@@ -538,11 +538,20 @@ is only meant for documentation purposes and doesn't carry any semantics.
 === Mocking Classes
 
 Besides interfaces, Spock also supports mocking of classes. Mocking classes works
-just like mocking interfaces; the only additional requirement is to put `cglib-nodep-2.2` or higher
-and `objenesis-1.2` or higher on the class path. If either of these libraries is missing from
-the class path, Spock will gently let you know.
+just like mocking interfaces; the only additional requirement is to put `byte-buddy` 1.9+ or
+`cglib-nodep` 3.2.0+ on the class path.
 
-NOTE: Java 8 is only supported from CGLIB 3.2.0 onwards.
+When using for example
+
+- normal ``Mock``s or ``Stub``s or
+- ``Spy``s that are configured with `useObjenesis: true` or
+- ``Spy``s that spy on a concrete instance like `Spy(myInstance)`
+
+it is also necessary to put `objenesis` 3.0+ on the class path, except for classes with accessible
+no-arg constructor or configured `constructorArgs` unless the constructor call should not be done,
+for example to avoid unwanted side effects.
+
+If either of these libraries is missing from the class path, Spock will gently let you know.
 
 == Stubbing
 

spock-core/src/main/java/org/spockframework/mock/runtime/MockInstantiator.java

@@ -33,7 +33,7 @@ public static Object instantiate(Class<?> declaredType, Class<?> actualType, @Nu
       return GroovyRuntimeUtil.invokeConstructor(actualType, constructorArgs == null ? null : constructorArgs.toArray());
     } catch (Exception e) {
       String msg = constructorArgs == null && useObjenesis && !objenesisAvailable ?
-          ". To solve this problem, put Objenesis 1.2 or higher on the class path (recommended), or supply " +
+          ". To solve this problem, put an up-to-date version of Objenesis on the class path (recommended), or supply " +
               "constructor arguments (e.g. 'constructorArgs: [42]') that allow to construct an object of the mocked type." : null;
       throw new CannotCreateMockException(declaredType, msg, e);
     }