public static void notNull(Object object) {
        notNull(object, "[Assertion failed] - this argument is required; it must not be null");
    }
Assert that an object is not <code>null</code> .
<pre class="code">Assert.notNull(clazz);</pre>
@param object the object to check
@throws IllegalArgumentException if the object is <code>null</code>
src/main/java/org/apache/shiro/lang/util/Assert.java