title: @NotNull not working as expected
body: <p>I have a method like:</p>
  
  <pre><code>public String getParamValue(@NotNull String param) {
          .......
          .......
          .......
      }
  </code></pre>
  
  <p>Even after putting <code>@NotNull</code> in-front of the <code>param</code>, whenever i am calling <code>getParamValue(null)</code> it is not throwing <code>NPE</code>. It proceeds as normal, do i need to do something else or am i using it wrongly? Thanks. </p>
  
  <p>I am using Java 7 and <code>javax.validation.constraints.NotNull</code> if it helps in any ways.</p>