anchor.diff:  
   See the answer at the end.
   
  +=== null reference
  +
  +What does this do?
  +
  +[source, Java]
  +----
  +Thread t = null; 
  +t.yield();
  +----
  +
  +1. A compiler error
  +1. A runtime error
  +1. The JVM crashes
  +1. The JVM pauses briefly
  +
  +What does this do?
  +
   == Answers
   
   === void arrays
  
positive.code: = Java Quiz
  Peter Lawrey
  :published_at: 2019-01-31
  
  Here are some odd quiz question in Java which might have interesting answers.
  
  == Questions
  
  
negative.code: <3> Also creates an empty `Void[]`
  <4> This triggers a runtime error, but not a compile error. The compiler has very little knowledge of how libraries work and doesn't pick this up as an issue.
  
  === null reference
  
  This code
  [source, Java]
  ----
  Thread t = null; 
  t.yield();
  ----
  is the same as
  [source, Java]
  ----
  Thread t = null; 
  Thread.yield(); // the method is static
  ----
  
  So the answer is 4 as it just pauses briefly.
  