title: How to add custom method to Spring Data JPA
body: <p>I am looking into Spring Data JPA. Consider the below example where I will get all the crud and finder functionality working by default and if I want to customize a finder then that can be also done easily in the interface itself.</p>
  
  <pre><code>@Transactional(readOnly = true)
  public interface AccountRepository extends JpaRepository&lt;Account, Long&gt; {
  
    @Query("&lt;JPQ statement here&gt;")
    List&lt;Account&gt; findByCustomer(Customer customer);
  }
  </code></pre>
  
  <p>I would like to know how can I add a complete custom method with its implementation for the above AccountRepository? Since its an Interface I cannot implement the method there.</p>