title: What is the purpose of the default keyword in this scene
body: <p>I saw a question, which looks like this:</p>
  
  <pre><code>public @interface Controller {
  
  /**
   * The value may indicate a suggestion for a logical component name,
   * to be turned into a Spring bean in case of an autodetected component.
   * @return the suggested component name, if any
   */
  String value() default "";
  </code></pre>
  
  <p>}</p>
  
  <p>What is the default keyword, and the "" after default?</p>