title: Java regex "[.]" vs "."
body: <p>I'm trying to use some regex in Java and I came across this when debugging my code.</p>
  
  <p>What's the difference between <code>[.]</code> and <code>.</code>?</p>
  
  <p>I was surprised that <code>.at</code> would match "cat" but <code>[.]at</code> wouldn't.</p>