public void setNotValidBefore(java.util.Date notValidBefore) {
        this.notValidBefore = notValidBefore;
    }
<p>
The certificate is not valid before this date.
</p>

@param notValidBefore
       The certificate is not valid before this date.
aws-java-sdk-workspacesweb/src/main/java/com/amazonaws/services/workspacesweb/model/Certificate.java