 <p>As also said in documentation, <a href="http://docs.jboss.org/hibernate/validator/4.2/api/org/hibernate/validator/constraints/NotBlank.html">@NotBlank</a> is for String type. There is no concept of java.util.Date being blank. It can be null or not null. </p> <blockquote> <p>Validate that the annotated string is not null or empty. The difference to NotEmpty is that trailing whitespaces are getting ignored.</p> </blockquote> <p>If goal is to check is value not null, <a href="http://docs.oracle.com/javaee/6/api/javax/validation/constraints/NotNull.html">@NotNull</a> should be used. According documentation:</p> <blockquote> <p>The annotated element must not be null. Accepts any type.</p> </blockquote>