request.getScheme() method is returning wrong value

I have a https-https redirection code in a jsp. I am trying to apply the redirection logic via the following code :

String uri         = request.getRequestURI();
String servername  = request.getServerName();
String contextPath = request.getContextPath();
String scheme      = request.getScheme();
int portname       = request.getServerPort();

if(scheme.startsWith("https")){
	  String port = workBean.getProperty("SSLPort");
      response.sendRedirect("https://"+servername+":"+ port +"/xyz/login.jsp");
} else {
	  String port = workBean.getProperty("HttpPort");
      response.sendRedirect("http://"+servername+":"+port+"/xyz/login.jsp");
}

However the if condition is not correctly working for https. I am using a load balancer for https.

Please tell me where I am doing wrong and how to fix the issue.

If you are using a load balancer, did you try to check for the header X-Forwarded-Proto. Many load balacers/proxies set this header or you can configure them to set this header.

Depending on what servlet container you are using and how it is configured the value of the header X-Forwarded-Proto is sometimes directly used by the scheme field.

But also you could read the header yourself from the request and use it instead of the scheme if it's available.

> The X-Forwarded-Proto (XFP) header is a de-facto standard header for identifying the protocol (HTTP or HTTPS) that a client used to connect to your proxy or load balancer. [...] To determine the protocol used between the client and the load balancer, the X-Forwarded-Proto request header can be used.

https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-Proto