title: The method fun(String) is ambiguous for the type TestInterviewquestion class
body: <p>This public class <code>TestInterviewquestion</code> has these methods and all parameters are unique. But I get the compile time error <em>"The method fun(String) is ambiguous for the type TestInterviewquestion class"</em>.
  Can someone see the problem?</p>
  
  <pre><code>public static void fun(String s) {
      System.out.println("String");
  }
  
  public static void fun(Object o) { 
      System.out.println("Object");
  }
  
  public static void fun(Integer i) {
      System.out.println("Integer");
  }
  
  public static void main(String arg[]) {
      fun(null);
  }
  </code></pre>