title: What does the regular expression [.\d\D]* mean?
body: <p>What does <code>[.\\d\\D]*</code> mean. </p>
  
  <p>I am trying to check a valid java main method statement by</p>
  
  <pre><code>java.matches("[.\\d\\D]*((public)\\s(static)\\s(void)\\s(main)\\((String)\\[\\]\\s(args)\\))[.\\d\\D]*");
  </code></pre>
  
  <p>what does that part mean?</p>