getResponse().setContentType("text/html") returning nullpointer exception

I am having trouble understanding the http response in my servlet. I am outputting html to screen but its not working in IE9, i looked at posts that had similar issues and they seem to suggest that the response content type should be set to html for the browser to interpret as html. So I have tried adding the setcontent line just before I stream the html as per below

However it seems that the getResponse() is null and I am getting a null pointer exception.

My question is how can I get this to be not null, is there a way of creating a new instance of this? There is no get or post methods in the servlet and not sure what the best way of getting my html to execute in IE9, all other browsers work fine.

You'll need to post more context than just those two lines of code. Where do they exist? In what class? In what method?

HttpServlet doesn't even define a getRepsonse() method, the response is passed to the handler method. So what's defining getResponse()?