Object Oriented Class Communication
<p>I have a Java assessment that gets marked by a robot. Whenever I upload my assignment it shows a screen like this.</p>

<pre>
A good object-oriented design places each method into the most appropriate
class. The most appropriate class for a method should be the same class as
the data fields that that method needs to access. If you don't place a method
into the right class, then this will most likely increase the amount of
communication that is required between your classes.

The score below measures the amount of communication between your classes. A
lower score is better.

19 method invocations between classes
7 arguments passed between classes
15 results returned between classes

Amount of communication = invocations + 2*inputs + 2*outputs = 63
</pre>

<p>Now what exactly does "method invocations between classes", "arguments passed between classes" and "results returned between classes" mean?</p>
