title: Java class can not be resolved to a type? Java(16777218)
body: <p>I created a class called Currency and Exchangeable which is implemented into Saturn, Neptune, and Mars. The three classes extend Currency and implement Exchangeable. When I try to refer to them in my main method it gives me an error &quot;{class name} can not be resolved to a type&quot;.</p>
  <p>Here is currency:</p>
  <pre><code>public abstract class Currency {
      String currencyName;
      double totalFunds;
      public abstract double toEarthDollars(double amount);
      public abstract double fromEarthDollars(double EarthDollars);
  }
  </code></pre>
  <p>Below is my main class(Errors are bolded):</p>
  <pre><code>public static void main(String[] args){
          Currency mars = new **Mars**(100.00); Currency neptune = new **Neptune**(100.00); 
          Currency saturn = new Saturn(100.00);
          System.out.println(&quot;&lt;-- Exchanges --&gt;&quot;);
          mars.**exchang**e(saturn, 25.0); neptune.**exchange**(saturn, 10.0); 
          saturn.**exchange**(mars, 122.0); saturn.**exchange**(mars, 121.0);
          
      } 
  </code></pre>