title: How to run code after constructor in a Lombok builder
body: <p>I have a class that I want to use Lombok.Builder and I need pre-process of some parameters. Something like this:</p>
  
  <pre><code>@Builder
  public class Foo {
     public String val1;
     public int val2;
     public List&lt;String&gt; listValues;
  
     public void init(){
         // do some checks with the values.
     }
  }
  </code></pre>
  
  <p>normally I would just call <code>init()</code> on a NoArg constructor, but with the generated builder I'm unable to do so. Is there a way for this <code>init</code> be called by the generated builder? For example <code>build()</code> would generate a code like:</p>
  
  <pre><code>public Foo build() {
     Foo foo = Foo(params....)
     foo.init();
     return foo;
  }
  </code></pre>
  
  <p>I'm aware that I can manually code the <code>all args</code> constructor, that the Builder will call through it and I can call <code>init</code> inside there.</p>
  
  <p>But that is a sub-optimal solution as my class will likely have new fields added every once in a while which would mean changing the constructor too.</p>