Captcha & reCaptcha with Liferay 7

If you are planning to integrate captcha in you liferay custom portlet then use below stuff

view.jsp:
<%@taglib uri="http://liferay.com/tld/captcha" prefix="liferay-captcha" %>
<portlet:resourceURL id="/login/captcha" var="captchaURL"/>
<liferay-captcha:captcha url="<%=captchaURL%>" />


Write CaptchaMVCResourceCommand.java :

@Component(
    property = {
        "javax.portlet.name=test_portlet",
        "mvc.command.name=/login/captcha"
    },
    service = MVCResourceCommand.class
)
public class CaptchaMVCResourceCommand extends BaseMVCResourceCommand {

    @Override
    public boolean serveResource(
        ResourceRequest resourceRequest, ResourceResponse resourceResponse) {

        try {
            CaptchaUtil.serveImage(resourceRequest, resourceResponse);
            return false;
        }
        catch (Exception e) {
            _log.error(e, e);

            return true;
        }
    }

And you are done...

Make sure you use <liferay-captcha:captcha url="<%=captchaURL%>" />  instead of <liferay-ui:captcha url="<%=captchaURL%>" /> as its not support in custom module somehow.