title: Java List vs ArrayList
body: <p>As a C++ oldtimer I have managed to solve my problem but I can not wrap my head around the underlying Java mechanisms here: </p>
  
  <pre><code>Vector&lt;Object&gt; x = new Vector&lt;Object&gt;();        // OK
  ArrayList&lt;Object&gt; y = new ArrayList&lt;Object&gt;();  // OK
  List&lt;Object&gt; zzz = new ArrayList&lt;Object&gt;();     // OK solves problem below but question remains
  List&lt;Object&gt; z = new List&lt;Object&gt;();            // WHY? Compiler error: Cannot instantiate 
  </code></pre>