Because of the rule that zero input must cause zero output. But sometimes we may want to take some action if the servlet has no output.
null: which will be automatically written when all the output is zero and the servlet exited normally
error: which will be automatically written after the servlet's return code is a failure
Because of the rule that zero input must cause zero output. But sometimes we may want to take some action if the servlet has no output.
null: which will be automatically written when all the output is zero and the servlet exited normally error: which will be automatically written after the servlet's return code is a failure