title: Check if a string is instance of a Class in Java
body: <p>I would like to know how to check if a string is instance of a Class in a Server Side of ServerSocket programm. Α client gives an object of class Myclass1 and the server must check if a string that reads from client is instance of MyClass1 or another class(e.g. MyClass2, String, Integer, etc.)</p>
  
  <p>That is my code: </p>
  
  <pre><code>  ObjectInputStream object_input = new ObjectInputStream(sock.getInputStream());
    String string = object_input.readLine();
    if (string instanceof MyClass1){...}
    else if(string instanceof MyClass2){...}
  </code></pre>
  
  <p>It makes an error and I don't know how to solve it. Please, help me</p>