Connecting to PostgreSQL in java app engine

Connecting to PostgreSQL in java app engine

I'm trying to connect to PostgreSQL server from java app engine. On my
local machine code works perfectly, but when I deploy code to appengine, I
get this exception:
Uncaught exception from servlet
java.lang.NullPointerException
at
com.google.appengine.runtime.Request.process-3a02a4d7b73299fa(Request.java)
at java.util.Hashtable.put(Hashtable.java:432)
at java.util.Properties.setProperty(Properties.java:161)
at org.postgresql.Driver.loadDefaultProperties(Driver.java:121)
at org.postgresql.Driver.access$000(Driver.java:46)
at org.postgresql.Driver$1.run(Driver.java:88)
at java.security.AccessController.doPrivileged(AccessController.java:63)
at org.postgresql.Driver.getDefaultProperties(Driver.java:85)
at org.postgresql.Driver.connect(Driver.java:231)
at java.sql.DriverManager.getConnection(DriverManager.java:579)
at java.sql.DriverManager.getConnection(DriverManager.java:221)
at guestbook.PostgreServlet.doGet(PostgreServlet.java:49)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at
org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
at
com.google.appengine.tools.appstats.AppstatsFilter.doFilter(AppstatsFilter.java:141)
at
org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at
org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at
org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at
org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at
org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at
org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at
org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at
org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at
org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at
org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at
org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at
org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at
com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:435)
at
com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:442)
at
com.google.tracing.CurrentContext.runInContext(CurrentContext.java:186)
at
com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:306)
at
com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:298)
at
com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:439)
at java.lang.Thread.run(Thread.java:722)
I am using postgresql-9.2-1003.jdbc4.jar and I have this jdbc as library
and also inside my "war/WEB-INF/lib" folder. My java code is here:
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.logging.Logger;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class PostgreServlet extends HttpServlet {
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
resp.setContentType("text/html");
PrintWriter pw = resp.getWriter();
Connection conn = null;
String result = "";
try {
conn =
DriverManager.getConnection("jdbc:postgresql://xx.xxx.xxx.xxx:xxxx/xxxxx",
"xxx", "xxxx");
if(conn == null){
pw.println("Connection null");
return;
}
ResultSet rs = conn.createStatement().executeQuery(
"SELECT * FROM pg_catalog.pg_tables");
while (rs.next()) {
result += rs.getString("tablename") + "<br>";
}
pw.println(result);
} catch (SQLException e) {
e.printStackTrace();
}
finally {
if(conn != null){
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}