title: Donor does not define a no-argument constructor. If you are using ProGuard, make sure these constructors are not stripped
body: <p>How do I solve the problem?</p>
  <pre class="lang-java prettyprint-override"><code>package com.example.blood_donor;
  
  public class Donor {
  
      private final String name;
      private final String age;
      private final String mobile;
      
      private final String state;
      private final String city;
      private final String gender;
      private final String blood;
      private final String mail;
      private final String pin;
  
  }
  </code></pre>