Doubt for exist bug (read JSON format)

Doubt for exist bug (read JSON format)

I think that exist Bug at the JQuery .
at the 1.5.1,check for read Json format with JSP file ,JQuery can't read this format.
can you check it?
for example :
$.ajax({
 url: "server.jsp",
 dataType: 'json',
 success: function(data){
 alert(data.one); 
 }


});
jquery can't read Data in the "server.jsp".but at the :
$.ajax({
 url: "server.txt",
 dataType: 'json',
 success: function(data){
 alert(data.one); 
 }


});
very easy read data in the "server.txt" file.









Can you check it?