code: public void assertNotNull(Description description, Object actual) {
      if (actual == null) {
        throw failures.failure(description, shouldNotBeNull());
      }
    }
docs: Asserts that the <em>actual</em> object is not {@code null}.
  
  @param description the description of the <em>actual</em> object.
  @param actual the <em>actual</em> object.
  @throws AssertionError if the <em>actual</em> object is {@code null}.