Need help with JDBC code walk

S

soup_or_power

Hello Everyone

I am in a soup again :) I have a java class called SessionManager. As
its name implies, it keeps track of session.getAttribute and
session.setAttribute calls from a webserver (actually JSF + JBOSS
which is another nightmare :).

This is the crux: when I take away the JDBC calls everything works
fine except for the session persistence between server reboots. I
looked very hard and long at the code for almost a week now. Problem
is it works some times. I am unable to determine any pattern as to
what causes the code to fail. Could it be serialization of objects in/
out of Mysql? To go through every object that is ever put into a
session, it is a very lengthy task given that I am maintaining the
code (am not the writer of JSF back end beans).

I looked into some session persistence solutions (can't remember off
hand) and found them to be useful for a new project. Even using
hibernate is not an option for me. Since I already worked on this code
for several weeks now and the fact that it works some times, makes me
an optimist. :) Please help me out if you can.

BTW, these are the versions: jvm 1.5, jboss 4.0.2, Windows XP

Imports not shown... no compile problems....run time errors like
objects returned null; Typically the select component of JSF gets a
null enumeration.

Thanks


/**
* This class provides methods to interact with the session. Its
exposes methods to put and get objects into
* Session and also exposes methods to do cleanup.
* @author rajasekhark
*/
public class SessionManager {

/**
* Sets an attribute in the session. These attributes would be
independent of the module,
* and would be removed when the session expires. Or
<code>flush(HttpSession session)</code>
* is called in the session.
* @param key
* @param value
* @param session
* @throws InvalidParameterException
*/
public static void setAttribute(String key, Object value,
HttpSession session)
throws InvalidParameterException{

if (value == null) {
System.out.println("***********set attribute value null");
System.exit(0);
}

String sessid = (String)session.getId();
System.out.println("sessionid=" + sessid);
//open db connection and save attribute if UID is set
UserContext ucon = (UserContext)
session.getAttribute(FrameworkConstants.UserContextKey);
String uid="";
if (ucon != null)
uid=ucon.getUid();
String uname="";
if (ucon != null) uname=ucon.getStrUserName();
if (uname == null) uname="";
System.out.println("SET ATTRIBUTE ******************uid=" + uid + "
uname=" + uname);
if (!sessid.equals("notset") && uid !=null && !uid.equals("")) {
Connection conn = null;
ResultSet rs=null;
PreparedStatement ps=null;


try
{
String userName = "jboss";
String password = "*********";
String url = "jdbc:mysql://localhost:3306/jsfsession";
Class.forName ("com.mysql.jdbc.Driver").newInstance ();
conn = DriverManager.getConnection (url, userName,
password);
System.out.println ("Setattribute Database connection
established for key=" + key);
ps = conn.prepareStatement("update session_tbl set val=?,
datestamp=NOW() where keyid=? and sessid=?");
ps.setString(3, sessid);
System.out.println("sessid=" + sessid);
System.out.println("userid=" + uid);
ps.setString(2, key);
System.out.println("key=" + key);
ByteArrayOutputStream baos1 = new ByteArrayOutputStream();
ObjectOutputStream oout1 = new ObjectOutputStream(baos1);
oout1.writeObject(value);
oout1.close();
ps.setBytes(1, baos1.toByteArray());
//ps.setObject(1, value);
System.out.println("set blob");

int r=ps.executeUpdate();

ps.close();
if (r==0) {
System.out.println("can't update");
ps = conn.prepareStatement("insert into session_tbl (sessid, uid,
keyid, val, uname, datestamp) values (?, ?, ?, ?, ?, NOW())");
ps.setString(1, sessid);
System.out.println("uid=" + uid);
ps.setString(2, uid);
ps.setString(3, key);
System.out.println("key=" + key);
ByteArrayOutputStream baos2 = new ByteArrayOutputStream();
ObjectOutputStream oout2 = new ObjectOutputStream(baos2);
oout2.writeObject(value);
oout2.close();
ps.setBytes(4, baos2.toByteArray());
//ps.setObject(4, value);
System.out.println("set blob");
ps.setString(5, uname);
ps.executeUpdate();
System.out.println("insert successful");
}
ps.close();
}
catch (Exception e)
{
System.err.println ("Cannot connect to database server"
+ e.getMessage());
}
finally
{
if (ps != null) {
try {
ps.close();
} catch (Exception e2) {};
}
if (conn != null)
{
try
{
conn.close ();
System.out.println ("Setattribute Database
connection terminated");
}
catch (Exception e) { /* ignore close errors */ }
}
}
} //if
try{

//checks if the key is null or empty. Throws an exception if
it is.
if(null == key || "" == key){
Object [] values = new Object[1];
values[0] = "key";
throw new
InvalidParameterException("InvalidParameterException",values);
}//end-if
//checks if the session is null or empty. Throws an
exception if it is.
if(null == session){
Object [] values = new Object[1];
values[0] = "session";
throw new
InvalidParameterException("InvalidParameterException",values);
}//end-if

//set the session attribute
session.setAttribute(key, value);
System.out.println("setting attr in session key=" + key + " value="
+ value);
}catch(RuntimeException ex){
throw new InvalidParameterException(ex);
}//end-try-catch
System.out.println("leaving set attribute");
}//end setAttribute

/**
* Sets an attribute in the session. These attribute pattern would
be the module name, and would
* be removed when the session expires. Or <code>flush(String
pattern, HttpSession session)</code>
* is called in the session.
* @param pattern
* @param key
* @param value
* @param session
* @throws InvalidParameterException
*/
public static void setPatternedAttribute(String pattern, String key,
Object value, HttpSession session)
throws
InvalidParameterException{
System.out.println("entered set patterned attribute");
try{

//checks if the key is null or empty. Throws an exception if
it is.
if(null == key || "" == key){
Object [] values = new Object[1];
values[0] = "key";
throw new
InvalidParameterException("InvalidParameterException",values);
}//end-if
//checks if the session is null or empty. Throws an
exception if it is.
if(null == session){
Object [] values = new Object[1];
values[0] = "session";
throw new
InvalidParameterException("InvalidParameterException",values);
}//end-if

//set the session attribute
session.setAttribute(pattern + "_" + key, value);
System.out.println("setting pattern=" + pattern + " key=" + key + "
value=" + value);
}catch(RuntimeException ex){
throw new InvalidParameterException(ex);
}//end-try-catch
}

/**
* Gets the value corresponding to the key passed as parameter. It
iterates through all the
* available keys in the session, locates the key passed as
parameter. If found it passes the
* corresponding value, else it throws appropriate exception.
* @param key
* @param session
* @return Object
* @throws InvalidParameterException
* @throws SessionKeyNotFoundException
*/
public static Object getAttribute(String key, HttpSession session)
throws
InvalidParameterException,

SessionKeyNotFoundException{
System.out.println("entered get attribute*********");
String uid="";
UserContext ucon = (UserContext)
session.getAttribute(FrameworkConstants.UserContextKey);
String sessid="notset";
if (ucon != null)
uid=ucon.getUid();
System.out.println("*********uid=" + uid);
sessid=(String)session.getId();
System.out.println("session =" + sessid);

Enumeration enumSessionKeys = null;
Object returnValue = null;
boolean bKeyFound = false;
try{

//checks if the key is null or empty. Throws an exception if
it is.
if(null == key || key.equals("")){
Object [] values = new Object[1];
values[0] = "key";
throw new
InvalidParameterException("InvalidParameterException",values);
}//end-if
//checks if the session is null or empty. Throws an
exception if it is.
if(null == session){
Object [] values = new Object[1];
values[0] = "session";
throw new
InvalidParameterException("InvalidParameterException",values);
}//end-if

//Get all the keys available in session.
enumSessionKeys = session.getAttributeNames();

//Iterate through all the keys in the enumSessionKeys
enumeration. If the key
//is found populate returnValue with the corresponding
session value and set the
//key found flag to true. The first if checks for those
attributes that are set
//based on a key without a pattern. The second if is for the
attributes that are
//set in the session based on a pattern.
while(enumSessionKeys.hasMoreElements()){
if (key.indexOf("userContext") > -1) break;
String strCurrentKey =
(String)enumSessionKeys.nextElement();
CharSequence keySeq = key.subSequence(0, key.length());
System.out.println("keyinput=" + key + "keyseq=" +
keySeq + " strCurrentKey=<" + strCurrentKey + ">value=<" +
session.getAttribute(strCurrentKey));
if((strCurrentKey).equals(key)){
returnValue = session.getAttribute(key);
bKeyFound = true;
System.out.println("match1");
break;
}//end-if
else if(strCurrentKey.endsWith(key)){
returnValue = session.getAttribute(strCurrentKey);
bKeyFound = true;
System.out.println("match2");
break;
}//end-else-if
else if((strCurrentKey).contains(keySeq)){
returnValue = session.getAttribute(strCurrentKey);
bKeyFound = true;
System.out.println("match3");
break;
}//end-else-if


}


if (bKeyFound) {
System.out.println("Key = " + key + " is found");
if (returnValue != null) return returnValue;
} else {
System.out.println("key=" + key + " not found");
}
//
//open db connection and save attribute IF the attribute is not
found
if ( !sessid.equals("notset") ) {
Connection conn = null;
ResultSet rs=null;
PreparedStatement ps=null;
try
{
String userName = "jboss";
String password = "**************";
String url = "jdbc:mysql://localhost:3306/jsfsession";
Class.forName ("com.mysql.jdbc.Driver").newInstance ();
conn = DriverManager.getConnection (url, userName,
password);
System.out.println ("Getattribute Database connection
established. looking for key=" + key);
ps = conn.prepareStatement("select val from session_tbl where
keyid ='" + key + "' and sessid=? order by datestamp ASC");
ps.setString(1, sessid);

//ps.setString(1, strCurrentKey);
rs=ps.executeQuery();
if (rs.next()) {
bKeyFound=true;
System.out.println("Found it!");

byte[] buf = rs.getBytes("val");
if (buf != null) {
System.out.println("buf not null in getattribute***********");
ObjectInputStream objectIn = new ObjectInputStream(
new ByteArrayInputStream(buf));
returnValue = objectIn.readObject(); //Contains the object

}
//returnValue = rs.getObject("val");
}
rs.close();

ps.close();
if (!bKeyFound) {
ps = conn.prepareStatement("select val from session_tbl where keyid
like '%" + key + "' and sessid=? order by datestamp ASC");
ps.setString(1, sessid);

//ps.setString(1, strCurrentKey);
rs=ps.executeQuery();
if (rs.next()) {
bKeyFound=true;
System.out.println("Found it!");

byte[] buf = rs.getBytes("val");
if (buf != null) {
System.out.println("buf not null in getattribute***********");
ObjectInputStream objectIn = new ObjectInputStream(
new ByteArrayInputStream(buf));
returnValue = objectIn.readObject(); //Contains the object

}
//returnValue = rs.getObject("val");
}
rs.close();

ps.close();
}//if
if (!bKeyFound) {
ps = conn.prepareStatement("select val from session_tbl where
(keyid like '%" + key + "%' or keyid like '%" + key + "' or keyid like
'%" + key + "%') and sessid=? order by datestamp ASC");
ps.setString(1, sessid);

//ps.setString(1, strCurrentKey);
rs=ps.executeQuery();
if (rs.next()) {
bKeyFound=true;
System.out.println("Found it!");

byte[] buf = rs.getBytes("val");
if (buf != null) {
System.out.println("buf not null in getattribute***********");
ObjectInputStream objectIn = new ObjectInputStream(
new ByteArrayInputStream(buf));
returnValue = objectIn.readObject(); //Contains the object

}
//returnValue = rs.getObject("val");
}
rs.close();

ps.close();
}//if
}
catch (Exception e)
{
System.err.println ("Cannot connect to database server"
+ e.getMessage());
}
finally
{
try {
rs.close();
} catch (Exception e3) {};

if (ps != null) {
try {
ps.close();
} catch (Exception e2) {};
}
if (conn != null)
{
try
{
conn.close ();
System.out.println ("Getattribute Database
connection terminated");
}
catch (Exception e) { /* ignore close errors */ }
}
}
}//if
if (bKeyFound) {
setAttribute(key, returnValue, session);

}



//check if the key found flag is set to true. if not then throw
SessionKeyNotFoundException.
if(!bKeyFound || returnValue == null ){
Object [] values = new Object[1];
values[0] = key;
System.out.println("SessionManager about to throw
SessionKeyNotFoundException key="+key);
throw new
SessionKeyNotFoundException("SessionKeyNotFoundException", values);
}//end-if



return returnValue;
}catch(RuntimeException ex){
throw new InvalidParameterException(ex);
}//end-try-catch

}//end getAttribute

/**
* Removes the keys that follow a specified pattern (specified in
the input) from the session.
* @param pattern
* @param session
* @throws InvalidParameterException
*/
public static void flush(String pattern, HttpSession session)
throws InvalidParameterException{
System.out.println("entered session flush");
Enumeration enumSessionKeys = null; //enumeration that will hold
all the keys in the session.
String key = ""; //key arrived while iterating.
try{

//checks if the key is null or empty. Throws an exception if
it is.
if(null == pattern || "" == pattern){
Object [] values = new Object[1];
values[0] = "pattern";
throw new
InvalidParameterException("InvalidParameterException",values);
}//end-if
//checks if the session is null or empty. Throws an
exception if it is.
if(null == session){
Object [] values = new Object[1];
values[0] = "session";
throw new
InvalidParameterException("InvalidParameterException",values);
}//end-if

//Get all the keys available in session.
enumSessionKeys = session.getAttributeNames();

//if the attributes in the session are not null, iterate
through all the available
//keys and check if the pattern passed as input matches the
current key. If so then
//remove the key from the session.
if(null != enumSessionKeys){
while(enumSessionKeys.hasMoreElements()){
key = (String)enumSessionKeys.nextElement();
if(key.startsWith(pattern)) {
session.removeAttribute(key);
System.out.println("flush remove attrib=" + key);
}//end-if
}//end-while
}//end-if

}catch(RuntimeException ex){
throw new InvalidParameterException(ex);
}//end-try-catch
System.out.println("leaving sessioni flush");
}//end-flush

/**
* Invalidates the entire session.
* @param session
* @throws InvalidParameterException
*/
public static void flush(HttpSession session)
throws InvalidParameterException{
System.out.println("entered flush2");
Enumeration enumSessionKeys = null;
String key = ""; //key arrived while iterating.
try{

//checks if the session is null or empty. Throws an
exception if it is.
if(null == session){
Object [] values = new Object[1];
values[0] = "session";
throw new
InvalidParameterException("InvalidParameterException",values);
}//end-if

session.invalidate();

}catch(RuntimeException ex){
throw new InvalidParameterException(ex);
}//end-try-catch

System.out.println("Leafving flush2");
}//end-flush

public static void fflush(HttpSession session)
throws InvalidParameterException{
System.out.println("*****************entered fflush2");


String sessid="notset";
//if (ucon != null)
//uid=ucon.getUid();
sessid=(String)session.getId();
System.out.println("sessionid=" + sessid);
Connection conn = null;
ResultSet rs=null;
PreparedStatement ps=null;
try
{
String userName = "jboss";
String password = "*************";
String url = "jdbc:mysql://localhost:3306/jsfsession";
Class.forName ("com.mysql.jdbc.Driver").newInstance ();
conn = DriverManager.getConnection (url, userName,
password);
System.out.println ("Getattribute Database connection
established");
ps=conn.prepareStatement("select uid from session_tbl where
sessid=?");
ps.setString(1, sessid);
rs=ps.executeQuery();
String uid="";
if (rs.next()) {
uid=rs.getString("uid");
}
rs.close();
if (uid != null && !uid.equals("")) {
System.out.println("**********removing session for uid=" + uid);
//UserManager.removeff(uid);
}
ps.close();
ps = conn.prepareStatement("delete from session_tbl where
sessid=?");
ps.setString(1, sessid);
ps.executeUpdate();

ps.close();
}
catch (Exception e)
{
System.err.println ("Cannot connect to database server"
+ e.getMessage());
}
finally
{
try {
rs.close();
} catch (Exception e3) {};

if (ps != null) {
try {
ps.close();
} catch (Exception e2) {};
}
if (conn != null)
{
try
{
conn.close ();
System.out.println ("Getattribute Database
connection terminated");
}
catch (Exception e) { /* ignore close errors */ }
}
}
System.out.println("*****************Leafving fflush2");
}//end-flush
public static void fflushbyuserid(String uname, String uid)
throws InvalidParameterException{
System.out.println("*****************entered fflush2 for user=" +
uname);


Connection conn = null;
ResultSet rs=null;
PreparedStatement ps=null;
try
{
String userName = "jboss";
String password = "******";
String url = "jdbc:mysql://localhost:3306/jsfsession";
Class.forName ("com.mysql.jdbc.Driver").newInstance ();
conn = DriverManager.getConnection (url, userName,
password);
System.out.println ("Getattribute Database connection
established");
/*******************
ps=conn.prepareStatement("select uid from session_tbl where uname=?");
ps.setString(1, uname);
rs=ps.executeQuery();
String nuid="";
if (rs.next()) {
nuid=rs.getString("uid");
}
rs.close();
ps.close();
ps = conn.prepareStatement("delete from session_tbl where
uname=?");
ps.setString(1, uname);
ps.executeUpdate();

ps.close();
*************************/
if (uid != null && !uid.equals(""))
UserManager.removeff(uid);
}
catch (Exception e)
{
System.err.println ("Cannot connect to database server"
+ e.getMessage());
}
finally
{
try {
rs.close();
} catch (Exception e3) {};

if (ps != null) {
try {
ps.close();
} catch (Exception e2) {};
}
if (conn != null)
{
try
{
conn.close ();
System.out.println ("Getattribute Database
connection terminated");
}
catch (Exception e) { /* ignore close errors */ }
}
}
System.out.println("*****************Leafving fflushbyuserid");
}//end-flush
}
 
L

Lew

This is the crux: when I take away the JDBC calls everything works
fine except for the session persistence between server reboots. I

There are some problems in the code, including in the JDBC, but I don't know
if they cause your trouble.
Imports not shown... no compile problems....run time errors like
objects returned null; Typically the select component of JSF gets a
null enumeration. ....
/**
* This class provides methods to interact with the session. Its
exposes methods to put and get objects into
* Session and also exposes methods to do cleanup.
* @author rajasekhark
*/
public class SessionManager {

/**
* Sets an attribute in the session. These attributes would be
independent of the module,
* and would be removed when the session expires. Or
<code>flush(HttpSession session)</code>
* is called in the session.
* @param key
* @param value
* @param session
* @throws InvalidParameterException
*/
public static void setAttribute(String key, Object value,
HttpSession session)
throws InvalidParameterException{

Crazy indentation and the lack of braces on 'if' blocks make for difficult
code to read.

Use logging instead of System.out.println(). (Even if you use println() for
debugging, it should be to System.err, but logging is much, much better.)

I'm just going to delete the superfluous System.out.println() lines. They
really don't belong in a Usenet listing anyway.
if (value == null) {
System.exit(0);

You said you're using JBoss? Don't use System.exit() in an application
container like JBoss or Tomcat or whatever.
}

String sessid = (String)session.getId();

You don't need to cast a String to a String.
UserContext ucon = (UserContext)
session.getAttribute(FrameworkConstants.UserContextKey);
String uid="";
if (ucon != null)
uid=ucon.getUid();
String uname="";

Indentation and braces - confusing when they aren't right.
if (ucon != null) uname=ucon.getStrUserName();
if (uname == null) uname="";
if (!sessid.equals("notset") && uid !=null && !uid.equals("")) {
Connection conn = null;
ResultSet rs=null;
PreparedStatement ps=null;

try
{
String userName = "jboss";
String password = "*********";
String url = "jdbc:mysql://localhost:3306/jsfsession";
Class.forName ("com.mysql.jdbc.Driver").newInstance ();

You only need to load the JDBC driver once per application run, not repeatedly
on every single freaking connection, and never need to instantiate it explicitly.
conn = DriverManager.getConnection (url, userName,
password);
ps = conn.prepareStatement("update session_tbl set val=?,
datestamp=NOW() where keyid=? and sessid=?");
ps.setString(3, sessid);
ps.setString(2, key);
ByteArrayOutputStream baos1 = new ByteArrayOutputStream();
ObjectOutputStream oout1 = new ObjectOutputStream(baos1);
oout1.writeObject(value);
oout1.close();

Luckily for you, ByteArrayOutputStreams don't close.
ps.setBytes(1, baos1.toByteArray());

int r=ps.executeUpdate();

ps.close();
if (r==0) {
ps = conn.prepareStatement("insert into session_tbl (sessid, uid,
keyid, val, uname, datestamp) values (?, ?, ?, ?, ?, NOW())");
ps.setString(1, sessid);
ps.setString(2, uid);
ps.setString(3, key);
ByteArrayOutputStream baos2 = new ByteArrayOutputStream();
ObjectOutputStream oout2 = new ObjectOutputStream(baos2);
oout2.writeObject(value);
oout2.close();
ps.setBytes(4, baos2.toByteArray());
ps.setString(5, uname);
ps.executeUpdate();

How come you don't check for the return value of this execution?
}
ps.close();
}
catch (Exception e)
{
System.err.println ("Cannot connect to database server"
+ e.getMessage());

You ignore this error after logging it. does you r log show any errors?

BTW, errors other than inability to connect will trigger this catch block.
Also, your error message is extremely weak; it would never help anyone in
operations track down an error.

As you might have seen for yourself by now.
}
finally
{
if (ps != null) {
try {
ps.close();
} catch (Exception e2) {};
}
if (conn != null)
{
try
{
conn.close ();
System.out.println ("Setattribute Database
connection terminated");
}
catch (Exception e) { /* ignore close errors */ }
}
}
} //if

Now suddenly you switch to a whole different functionality inside the same
method. Consider refactoring - it'll make bugs like yours easier to solve.
try{

//checks if the key is null or empty. Throws an exception if
it is.
if(null == key || "" == key){

Don't compare Strings with ==, use equals(). This test might be letting an
empty String through to the following logic. Would that cause your error?
Object [] values = new Object[1];
values[0] = "key";
throw new
InvalidParameterException("InvalidParameterException",values);

This exception is from the java.security package - probably not the right
package. What's wrong with java.lang.IllegalArgumentException?

That would be the normal choice.
}//end-if

Huh? "//end-if"? The block is only three lines long - did you think people
would forget?
if(null == session){
Object [] values = new Object[1];
values[0] = "session";
throw new
InvalidParameterException("InvalidParameterException",values);
}//end-if

//set the session attribute
session.setAttribute(key, value);
}catch(RuntimeException ex){
throw new InvalidParameterException(ex);

Since java.security.InvalidParameterException is already a RuntimeException,
and the only one that will be thrown by the try block, you are rethrowing the
original exception wrapped in another instance of the same type of exception.
Why catch-and-rethrow at all? You could just let the exception through.

The java.lang.IllegalArgumentException. Of which InvalidParameterException is
a subtype. From the java.security package, when this isn't a security error.
}//end-try-catch
System.out.println("leaving set attribute");
}//end setAttribute

You aren't doing a very good job of checking for or handling the various
SQLExceptions that could occur in your JDBC code. One of them might be
triggering the behavior you see.
 
S

soup_or_power

This is the crux: when I take away the JDBC calls everything works
fine except for the session persistence between server reboots. I

There are some problems in the code, including in the JDBC, but I don't know
if they cause your trouble.






Imports not shown... no compile problems....run time errors like
objects  returned null; Typically the select component of JSF gets a
null enumeration. ...
/**
 * This class provides methods to interact with the session. Its
exposes methods to put and get objects into
 * Session and also exposes methods to do cleanup.
 * @author rajasekhark
 */
public class SessionManager {
  /**
   * Sets an attribute in the session. These attributes would be
independent of the module,
   * and would be removed when the session expires. Or
<code>flush(HttpSession session)</code>
   * is called in the session.
   * @param key
   * @param value
   * @param session
   * @throws InvalidParameterException
   */
  public static void setAttribute(String key, Object value,
HttpSession session)
                                    throws InvalidParameterException{

Crazy indentation and the lack of braces on 'if' blocks make for difficult
code to read.

Use logging instead of System.out.println().  (Even if you use println() for
debugging, it should be to System.err, but logging is much, much better.)

I'm just going to delete the superfluous System.out.println() lines.  They
really don't belong in a Usenet listing anyway.
if (value == null) {
   System.exit(0);

You said you're using JBoss?  Don't use System.exit() in an application
container like JBoss or Tomcat or whatever.
   String sessid = (String)session.getId();

You don't need to cast a String to a String.
   UserContext ucon = (UserContext)
session.getAttribute(FrameworkConstants.UserContextKey);
   String uid="";
   if (ucon != null)
           uid=ucon.getUid();
           String uname="";

Indentation and braces - confusing when they aren't right.
   if (ucon != null) uname=ucon.getStrUserName();
if (uname == null) uname="";
if (!sessid.equals("notset") && uid !=null && !uid.equals("")) {
Connection conn = null;
ResultSet rs=null;
PreparedStatement ps=null;
           try
           {
               String userName = "jboss";
               String password = "*********";
               String url = "jdbc:mysql://localhost:3306/jsfsession";
               Class.forName ("com.mysql.jdbc.Driver").newInstance ();

You only need to load the JDBC driver once per application run, not repeatedly
on every single freaking connection, and never need to instantiate it explicitly.
               conn = DriverManager.getConnection (url, userName,
password);
 ps = conn.prepareStatement("update session_tbl set val=?,
datestamp=NOW() where keyid=? and sessid=?");
           ps.setString(3, sessid);
           ps.setString(2, key);
ByteArrayOutputStream baos1 = new ByteArrayOutputStream();
ObjectOutputStream oout1 = new ObjectOutputStream(baos1);
oout1.writeObject(value);
oout1.close();

Luckily for you, ByteArrayOutputStreams don't close.




ps.setBytes(1, baos1.toByteArray());
           int r=ps.executeUpdate();
           ps.close();
           if (r==0) {
             ps = conn.prepareStatement("insert into session_tbl (sessid, uid,
keyid, val, uname, datestamp) values (?, ?, ?, ?, ?, NOW())");
           ps.setString(1, sessid);
           ps.setString(2, uid);
           ps.setString(3, key);
           ByteArrayOutputStream baos2 = new ByteArrayOutputStream();
ObjectOutputStream oout2 = new ObjectOutputStream(baos2);
oout2.writeObject(value);
oout2.close();
ps.setBytes(4, baos2.toByteArray());
           ps.setString(5, uname);
           ps.executeUpdate();

How come you don't check for the return value of this execution?
}
           ps.close();
           }
           catch (Exception e)
           {
               System.err.println ("Cannot connect to database server"
+ e.getMessage());

You ignore this error after logging it.  does you r log show any errors?

BTW, errors other than inability to connect will trigger this catch block.
Also, your error message is extremely weak; it would never help anyone in
operations track down an error.

As you might have seen for yourself by now.




           }
           finally
           {
           if (ps != null) {
                   try {
                           ps.close();
                   } catch (Exception e2) {};
           }
               if (conn != null)
               {
                   try
                   {
                       conn.close ();
                       System.out.println ("Setattribute Database
connection terminated");
                   }
                   catch (Exception e) { /* ignore close errors */ }
               }
           }
} //if

Now suddenly you switch to a whole different functionality inside the same
method.  Consider refactoring - it'll make bugs like yours easier to solve.
      try{
          //checks if the key is null or empty. Throws an exception if
it is.
          if(null == key || "" == key){

Don't compare Strings with ==, use equals().  This test might be letting an
empty String through to the following logic.  Would that cause your error?
              Object [] values = new Object[1];
              values[0] = "key";
              throw new
InvalidParameterException("InvalidParameterException",values);

This exception is from the java.security package - probably not the right
package.  What's wrong with java.lang.IllegalArgumentException?

That would be the normal choice.
          }//end-if

Huh?  "//end-if"?  The block is only three lines long - did you think people
would forget?
          if(null == session){
              Object [] values = new Object[1];
              values[0] = "session";
              throw new
InvalidParameterException("InvalidParameterException",values);
          }//end-if
          //set the session attribute
          session.setAttribute(key, value);
      }catch(RuntimeException ex){
          throw new InvalidParameterException(ex);

Since java.security.InvalidParameterException is already a RuntimeException,
and the only one that will be thrown by the try block, you are rethrowing the
original exception wrapped in another instance of the same type of exception.
  Why catch-and-rethrow at all?  You could just let the exception through.

The java.lang.IllegalArgumentException.  Of which InvalidParameterException is
a subtype.  From the java.security package, when this isn't a security error.
      }//end-try-catch
   System.out.println("leaving set attribute");
  }//end setAttribute

You aren't doing a very good job of checking for or handling the various
SQLExceptions that could occur in your JDBC code.  One of them might be
triggering the behavior you see.

--
Lew- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

Lew, thanks for your comments. Some of your comments apply to the
legacy code. My code snippets are JDBC only. The Jboss+JSF is set to
store the session variables in the HTML as hidden elements. Apparently
it will only put the UI info in the hidden vars. The null exception is
happening when rendering the HTML page. Looks like Windows XP is not
the right OS to test this code. I will have to find a linux box to do
more testing. Sigh!
 
S

soup_or_power

Looks like the code walk helped me. All I had to do was move the
session.setAttribute(...) in the setAttribute method to precede the
JDBC calls. I still don't know why it fixed other than a hunch.
Logically no matter what happens in the JDBC, the try-catch-finally
should pan out and the next try-catch block that embeds the
session.setAttribute(...) should be executed. BTW, there are no return
statements in the method and the key=="" code has been there for a
long time. So don't think that is the problem. Any comments are
welcome. Thanks!
 

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