String userAgent = getThreadLocalRequest().getHeader("User-Agent");
// Escape data from the client to avoid cross-site script vulnerabilities.
SafeHtmlBuilder builder = new SafeHtmlBuilder();
SafeHtml safeHtml = builder//
.appendEscapedLines("Hello, " + person.getName() + "!")//
.appendHtmlConstant("<br>")//
.appendEscaped("I am running " + serverInfo + ".")//
.appendHtmlConstant("<br><br>")//
.appendEscaped("It looks like you are using: ")//