title: Modify existing line in file - Java
body: <p>I need some help or code examples to update an existing line.</p>
  
  <p>File contents:</p>
  
  <pre><code>Heinrich: 30
  George: 2020
  Fred: 9090129
  </code></pre>
  
  <p>Say if I wanted to update (write) George's value to say 300, how would I achieve this?</p>
  
  <p>EDIT: Or would it be better off just using YAML?</p>
  
  <p>Thanks.</p>