P4
When I am trying to access getErrorStream() of HttpURLConnection , its giving
java.lang.NullPointerException in a particular condition.
Here I have a small servlet which writes some error messages thru
response.sendError(HttpServletResponse.SC_NOT_FOUND, errorMsg.toString());
and a test client which accesses error stream thru
BufferedReader bin = new BufferedReader(new InputStreamReader(ucon.getErrorStream()));
This statement fails with the following exception :
java HttpTestClient
java.lang.NullPointerException
at java.io.Reader.<init>(Reader.java:61)
at java.io.InputStreamReader.<init>(InputStreamReader.java:55)
at HttpTestClient.main(HttpTestClient.java:27)
But interestingly when I access getErrorStream() after calling getResponseCode() on that connection then it works properly. I can read the error message from servlet in this case. Same servlet works fine always from browser. So I didnt see any problem from servlet side.
I have tested this on Solaris sparc 8 with merlin build92
HOw to reproduce:
=================
Attached the test servlet class and client class.
Servlet class:
===============
public class HttpErrStream extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException
{
try {
System.out.println("IN HttpErrStream servlets do get");
response.setContentType("text/html");
StringBuffer errorMsg = new StringBuffer(" <html> <head> ");
errorMsg.append("<title>*** Requested resource not found *** </title>");
errorMsg.append("</head> <body> ");
errorMsg.append("<h1> ***" + HttpServletResponse.SC_NOT_FOUND + " ***</h1> ");
errorMsg.append("<h1> *** Error stream checking ***</h1> ");
errorMsg.append("</body> </html> ");
response.sendError(HttpServletResponse.SC_NOT_FOUND, errorMsg.toString());
} catch(Exception exp) {
exp.printStackTrace();
}
} // End of doGet
} // End of class
Test client:
=============
import java.net.*;
import java.io.*;
public class HttpTestClient {
public static void main(String[] args) {
HttpURLConnection ucon = null;
int responseCode;
try {
URL url = new URL("http://javacup.sfbay.sun.com:8080/examples/servlet/HttpErrStream");
ucon = (HttpURLConnection) url.openConnection();
ucon.setDoInput(true);
ucon.setRequestMethod("GET");
//ucon.connect();
System.out.println(" Request method" + ucon.getRequestMethod());
//System.out.println(" Response code " + ucon.getResponseCode());
BufferedReader bin = new BufferedReader(new InputStreamReader(ucon.getErrorStream()));
String result = bin.readLine();
System.out.println("read message from servlet" + result);
ucon.disconnect();
}catch(Exception exp) {
exp.printStackTrace();
}
} // End of main
} // End of class
Output from the test client in both cases:
-------------------------------------------
When access ucon.getResponseCode() before accessing errorstream() output is:
java HttpTestClient
Request methodGET
Response code 404
read message from servlet<html><head><title>Apache Tomcat/4.0.1 - Error report</title><STYLE><!--H1{font-family : sans-serif,Arial,Tahoma;color : white;background-color : #0086b2;} BODY{font-family : sans-serif,Arial,Tahoma;color : black;background-color : white;} B{color : white;background-color : #0086b2;} HR{color : #0086b2;} --></STYLE> </head><body><h1>Apache Tomcat/4.0.1 - HTTP Status 404 - <html> <head> <title>*** Requested resource not found *** </title></head> <body> <h1> ***404 ***</h1> </body> </html> </h1><HR size="1" noshade><p><b>type</b> Status report</p><p><b>message</b> <u> <html> <head> <title>*** Requested resource not found *** </title></head> <body> <h1> ***404 ***</h1> </body> </html> </u></p><p><b>description</b> <u>The requested resource ( <html> <head> <title>*** Requested resource not found *** </title></head> <body> <h1> ***404 ***</h1> </body> </html> ) is not available.</u></p><HR size="1" noshade></body></html>
Second case when I dont access getResponseCode() before getErrorStream():
java HttpTestClient
Request methodGET
java.lang.NullPointerException
at java.io.Reader.<init>(Reader.java:61)
at java.io.InputStreamReader.<init>(InputStreamReader.java:55)
at HttpTestClient.main(HttpTestClient.java:27)
java.lang.NullPointerException in a particular condition.
Here I have a small servlet which writes some error messages thru
response.sendError(HttpServletResponse.SC_NOT_FOUND, errorMsg.toString());
and a test client which accesses error stream thru
BufferedReader bin = new BufferedReader(new InputStreamReader(ucon.getErrorStream()));
This statement fails with the following exception :
java HttpTestClient
java.lang.NullPointerException
at java.io.Reader.<init>(Reader.java:61)
at java.io.InputStreamReader.<init>(InputStreamReader.java:55)
at HttpTestClient.main(HttpTestClient.java:27)
But interestingly when I access getErrorStream() after calling getResponseCode() on that connection then it works properly. I can read the error message from servlet in this case. Same servlet works fine always from browser. So I didnt see any problem from servlet side.
I have tested this on Solaris sparc 8 with merlin build92
HOw to reproduce:
=================
Attached the test servlet class and client class.
Servlet class:
===============
public class HttpErrStream extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException
{
try {
System.out.println("IN HttpErrStream servlets do get");
response.setContentType("text/html");
StringBuffer errorMsg = new StringBuffer(" <html> <head> ");
errorMsg.append("<title>*** Requested resource not found *** </title>");
errorMsg.append("</head> <body> ");
errorMsg.append("<h1> ***" + HttpServletResponse.SC_NOT_FOUND + " ***</h1> ");
errorMsg.append("<h1> *** Error stream checking ***</h1> ");
errorMsg.append("</body> </html> ");
response.sendError(HttpServletResponse.SC_NOT_FOUND, errorMsg.toString());
} catch(Exception exp) {
exp.printStackTrace();
}
} // End of doGet
} // End of class
Test client:
=============
import java.net.*;
import java.io.*;
public class HttpTestClient {
public static void main(String[] args) {
HttpURLConnection ucon = null;
int responseCode;
try {
URL url = new URL("http://javacup.sfbay.sun.com:8080/examples/servlet/HttpErrStream");
ucon = (HttpURLConnection) url.openConnection();
ucon.setDoInput(true);
ucon.setRequestMethod("GET");
//ucon.connect();
System.out.println(" Request method" + ucon.getRequestMethod());
//System.out.println(" Response code " + ucon.getResponseCode());
BufferedReader bin = new BufferedReader(new InputStreamReader(ucon.getErrorStream()));
String result = bin.readLine();
System.out.println("read message from servlet" + result);
ucon.disconnect();
}catch(Exception exp) {
exp.printStackTrace();
}
} // End of main
} // End of class
Output from the test client in both cases:
-------------------------------------------
When access ucon.getResponseCode() before accessing errorstream() output is:
java HttpTestClient
Request methodGET
Response code 404
read message from servlet<html><head><title>Apache Tomcat/4.0.1 - Error report</title><STYLE><!--H1{font-family : sans-serif,Arial,Tahoma;color : white;background-color : #0086b2;} BODY{font-family : sans-serif,Arial,Tahoma;color : black;background-color : white;} B{color : white;background-color : #0086b2;} HR{color : #0086b2;} --></STYLE> </head><body><h1>Apache Tomcat/4.0.1 - HTTP Status 404 - <html> <head> <title>*** Requested resource not found *** </title></head> <body> <h1> ***404 ***</h1> </body> </html> </h1><HR size="1" noshade><p><b>type</b> Status report</p><p><b>message</b> <u> <html> <head> <title>*** Requested resource not found *** </title></head> <body> <h1> ***404 ***</h1> </body> </html> </u></p><p><b>description</b> <u>The requested resource ( <html> <head> <title>*** Requested resource not found *** </title></head> <body> <h1> ***404 ***</h1> </body> </html> ) is not available.</u></p><HR size="1" noshade></body></html>
Second case when I dont access getResponseCode() before getErrorStream():
java HttpTestClient
Request methodGET
java.lang.NullPointerException
at java.io.Reader.<init>(Reader.java:61)
at java.io.InputStreamReader.<init>(InputStreamReader.java:55)
at HttpTestClient.main(HttpTestClient.java:27)