Stacktrace:] with Root Cause Java. Lang. Nullpointerexception

Stacktrace:] with Root Cause Java. Lang. Nullpointerexception

I am getting error at this point of code

org.apache.catalina.core.StandardWrapperValve invoke SEVERE: 

Servlet.service() for servlet [jsp] in context with path [/Work] threw exception [An exception occurred processing JSP page /Display.jsp at line 49 
46:<td> 
47: <% 
48: String sql="select * from Patient "; 
49: pstmt=con.prepareStatement(sql); 
50: rs=pstmt.executeQuery(); 
51: while(rs.next()){ 
52: %> 

Stacktrace:] with root cause java.lang.NullPointerException

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"""> <html> <head> 
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Insert title here</title> </head> 
<%@page import="java.sql.DriverManager"%> 
<%@page import="java.sql.ResultSet"%> 
<%@page import="java.sql.PreparedStatement"%>
 <%@page import="java.sql.Connection"%> 
<%@page import="com.connection.*"%> <body> 
<%! Connection con=null; 
PreparedStatement pstmt=null; 
ResultSet rs=null; 
public void init() { 
 try{ 
  Connection con = ConnectionImplementation.wantConnection();
    // Statement stmt= con.createStatement();
  } catch (Exception e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
  } 
} 
%> 
<table> 
<tr> <td>
 <select name="PERSON_TYPE" id="PERSON_TYPE"> 
<option value="">SELECT</option> 
<option value="Doctor">Doctor</option>
 <option value="Nurse">Nurse</option> 
<option value="Patient">Patient</option>
 </select> </td> 
</tr> 
<tr> <td> 
<% String sql="select * from Patient "; 
pstmt=con.prepareStatement(sql); 
rs=pstmt.executeQuery();
 while(rs.next()){ %> 
<tr><td> <%= rs.getInt(1)%></td> 
<td><%= rs.getString(2) %></td> 
<td><%= rs.getString(3) %></td> 
<td><%= rs.getInt(4) %></td> 
<td><%= rs.getString(5) %></td> 
<td><%= rs.getString(6) %></td> 
<td><%= rs.getString(7) %></td></tr> 
<% } %> </table> </body> </html>
1

1 Answer

Your member-variable con is never assigned a value thus null

Inside your init() method you declare a local variable con - so the member variable Connection con never changes from null to anything else.

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David Miller

David Miller brings 15 years of experience in global economics, personal finance strategy, and market dynamics. He specializes in turning complex economic trends into actionable insights for everyday readers.