Please solve my "java.lang.NullPointerException" error

My project is e learning project. I've a "choose the correct answer" module. When the click the "begin test" button it should fetch the questions and options from database and display it. Instead of that my page displays "java.lang.NullPointerException".
I've assigned unique values for each error. So the exact error it display as

"error occured 56 : java.lang.NullPointerException"

I have found the area of the error. but i couldn't solve it.
My codings are as follows

<html>
<%@ page import="INCLUDES.DBConnection"%>
<%@ page import="java.sql.*"%>
<%@ page import="java.io.*"%>
<jsp:useBean id="DB" scope="page" class="INCLUDES.DBConnection"/>
<jsp:setProperty name="DB" property="*"/>
<jsp:useBean id="DB1" scope="page" class="INCLUDES.DBConnection"/>
<jsp:setProperty name="DB1" property="*"/>
<jsp:useBean id="DB2" scope="page" class="INCLUDES.DBConnection"/>
<jsp:setProperty name="DB2" property="*"/>
<%
	
	String dbase=(String)session.getAttribute("dbase");
	String trainee_id=(String)session.getAttribute("trainee_id");
	String user_name=(String)session.getAttribute("user_name");
	if(user_name==null)
	{
		response.sendRedirect("course_list_index2.jsp");
	}
	int attempt_id=Integer.parseInt((String)session.getAttribute("attempt_id"));
	int number_of_questions=Integer.parseInt((String)session.getAttribute("number_of_questions"));
	int course_id=Integer.parseInt((String)session.getAttribute("course_id"));
	int paper_id=Integer.parseInt((String)session.getAttribute("paper_id"));
	String statement=null;
	ResultSet objRs=null;
	ResultSet objRsQNo=null;
	ResultSet objRsQ=null;
	int no_of_papers=0,paper_no=0;
	String course_name="",trainee_name="",paper_name="";
	try
	{
		statement="select * from x_master_elearning_user u,x_master_trainee_detail_online t,x_
masterListOfCourses c ,x_masterListOfPapers p where p.course_id=c.course_id and c.course_id=t.course_id
  and t.user_name=u.user_name and  c.course_id=" + course_id + " and u.user_name='" + user_name + "'
  and p.paper_id=" + paper_id;
		DB.setStatement(statement);
		objRs=(ResultSet)DB.result();
		if(objRs.next())
		{
			course_name=objRs.getString("course_name");
			trainee_name=objRs.getString("first_name");
			paper_name=objRs.getString("paper_name");
			no_of_papers=objRs.getInt("no_of_papers");
			paper_no=objRs.getInt("paper_no");
		}
	}
	catch(Exception e)
	{
		out.print("error occured 1 :" + e);
	}
	int i=0;
	if(request.getParameter("question_no")==null)
	{
		i=1;
	}
	else
	{
		i=Integer.parseInt(request.getParameter("question_no"))+1;
	}
	try
	{
			statement="select * from results where paper_id=" + paper_id + " and course_id=" + course_id
 + " and trainee_id='" + trainee_id + "'";
			DB1.setStatement(statement);
			objRsQNo=(ResultSet)DB1.result();
			if(objRsQNo.next())
			{
				if(i<= number_of_questions)
				{
						statement="select * from x_masterListOfQuestions where paper_id=" + paper_id
 + " and question_id=" + objRsQNo.getInt("qn" + i);
						DB2.setStatement(statement);
						objRsQ=(ResultSet)DB2.result();
				}
			}
				
	}
	catch(Exception e)
	{
		out.print("error occured 22  :" + e);
	}
%> 
<head>
<LINK href="theme/Master.css" rel="stylesheet" type="text/css">
<LINK rel="stylesheet" type="text/css" href="mystyle.css">
<TITLE>Help and Support</TITLE>
<SCRIPT language="JavaScript" src="ajaxfiles/ajaxfunction.js"></SCRIPT>
</HEAD>
<BODY class="backgrounpicture"  style="margin:0px">
<script src="topmenu.js"></script>
<form method="post" action="exam_question_insert.jsp" >
	           <input type="hidden" name="question_no" value=<%=i%>>	    
  <table width="75%" align="right"  >
    <tr> 
      <td colspan="3"><hr color="#FFFFff" noshade size="1"></td>
    </tr>
    <%
	try
	{    
		if(objRsQ.next())
		{
%>
    <tr > 
      <td width="9%" class="infoLabel">Q No.<strong><%=i%></strong></td>
      <td colspan="2" class="infoValue"><%=objRsQ.getString("question")%></td>
    </tr>
    <tr> 
      <td>  </td>
      <td colspan="2" class="infoValue"> <input type="radio" name="choice<%=i%>" value=1> 
        <%=objRsQ.getString("choice1")%></td>
    </tr>
    <tr> 
      <td> </td>
      <td colspan="2" class="infoValue"> <input type="radio" name="choice<%=i%>" value=2> 
        <%=objRsQ.getString("choice2")%></td>
    </tr>
    <tr> 
      <td> </td>
      <td colspan="2" class="infoValue"> <input type="radio" name="choice<%=i%>" value=3> 
        <%=objRsQ.getString("choice3")%></td>
    </tr>
    <tr> 
      <td> </td>
      <td colspan="2" class="infoValue"> <input type="radio" name="choice<%=i%>" value=4> 
        <%=objRsQ.getString("choice4")%></td>
    </tr>
    <%	  
		}
		
	}
	catch(Exception e)
	{
		out.print("error occured 56 : " + e);
	}	
	%>
    <tr> 
      <td colspan="3"><hr color="#FFFFff" noshade size="1"></td>
    </tr>
    <tr> 
      <td align=center> </td>
      <td align="right"> 
        <%if(i== number_of_questions)
			{
			%>
        <div align="right"> 
          <input type="submit" value="Finish" style="font-size:13pt;" name="submit" onClick="return fnConfirm()">
          <%
			}
			else
			{
			%>
          <input type="submit" value="Next" style="font-size:13pt;" name="submit">
          <%
			}
			%>
        </div></td>
      <td width="47%" align="right"><input type="submit" value="Review" style="font-size:13pt" name="submit"></td>
    </tr>
  </table>
</form>
       </body>
</html>

Please help me to solve this error. i'll be very thankful to you. If you need extra code tell me which part you want to solve this error. I'll post here. thanks to everyone. A little piece of help also appriciated

Step 1: Move the Java code out of the JSP and into a Java class where it belongs. Not only is this a best practice (while putting Java code into a JSP is most definitely not), it will make the code easier to debug.

The line number in the stack is pointing to a line of Java code in the generated Servlet source file, not the JSP.

Depending on which container you're using the actual source file (if saved) will be in different places.
Much easier to solve if your Java code is somewhere other than your JSP.

Most likely objRsQ is null, since that's the only Java operation happening in the try/catch block for error "56"--is there a compelling reason to use completely arbitrary numbers, of all things, to indicate where an error occurred?! How about something like: "Error while trying to display info from the result set" or something that's actually relevant and useful? Just an idea.

In any case, it's almost impossible to make sense of what you're doing: besides all the Java code in a JSP (booooo! :) the random indentation makes understanding any sort of structure much more difficult than necessary.