title: The use of ":" and "." in a call to java with classpath declaration
body: <p>This is a scjp mock exam question.</p>
  
  <p>Suppose I have the following two files:</p>
  
  <pre><code>package pkg;
  
  public class Kit {
      public String glueIt (String a, String b) {return a+b;}
  }
  
  import pkg.*;
  
  class UseKit {
      public static void main(String[]args) {
          String s = new Kit().glueIt(args[1],args[2]);
          System.out.println(s);
      }
  }
  </code></pre>
  
  <p>And the following directory structure:</p>
  
  <pre><code>test
     |--UseKit.class
     |
     com
       |--KitJar.jar
  </code></pre>
  
  <p>The current directory is <code>test</code> and the file <code>pkg/Kit.class</code> is in <code>KitJar.jar</code></p>
  
  <p>According to the answer, the java invocation that produces the output b c is</p>
  
  <pre><code>java -classpath com/KitJar.jar:. UseKit a b c 
  </code></pre>
  
  <p>Please explain the use of the operators ":" and "." </p>