title: Hibernate validator regex not resolved correctly
body: <p>I'm validating a class with the following annotation :</p>
  
  <pre><code>@Pattern(regexp = "^(00330|330)\\d{9}$", message="${msidsn.bad.format}")
  private String msisdn;
  </code></pre>
  
  <p>where I want to validate all numbers starting with 00330 or 330 and followed by whatever 9 digits.</p>
  
  <p>The pattern works fine with the usual java regex but always fails with the hibernate validator...</p>
  
  <pre><code>Set&lt;ConstraintViolation&lt;SMSObject&gt;&gt; constraintViolations =  validator.validate(sms);
  </code></pre>
  
  <p>→ Returns a ConstraintViolation.</p>
  
  <p>Normal regex checks fine :</p>
  
  <pre><code>boolean valid = false;
  Pattern pattern = Pattern.compile("^(00330|330)\\d{9}$");
  Matcher matcher = pattern.matcher("00330112345678");
  if (matcher.find()) {
      valid = true;
  }
  </code></pre>
  
  <p>Any insights on this would be much appreciated.</p>