CODEWITHSUNDEEP
javajsp
8900120dd
8900120dd

Reputation: 21

jsp and .equals and .trim() null pointer exception

this might be a pretty stupid question, im trying to figure out why im getting a null exception, please help. 

String username = (String)session.getAttribute("username");

if (!username.equals("ADMIN")) {
   request.setAttribute("Error", "You are not the admin");
   RequestDispatcher rd = request.getRequestDispatcher("LoginPage.jsp");
   rd.forward(request,response);
}

im trying to get the jsp to check whether the username equals "ADMIN", if it doesnt equal admin then it will give an error and then request the login page.

but i get a null pointer exception for line:

if (!username.equals("ADMIN")) {

thanks

Upvotes: 0

Views: 5394

Answers (2)

sanbhat
sanbhat

Reputation: 17622

thats because username is null

Best practice is to say if (!"ADMIN".equals(username))

Since a constant String "ADMIN" is a non-null value, invoking equals() on it will not cause any error and will be safe

OR do a null check on username before comparing:

if (username != null && !username.equals("ADMIN"))

Upvotes: 2

Jason
Jason

Reputation: 13966

Looks like username is null, i.e. not stored in the session. If using an IDE like Eclipse, you can put a breakpoint in, hover over the term with your mouse, and see what is null.

Upvotes: 0

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