java.lang.nullpointerexception

[Jaikiran mathukumalli]

I am a beginner in java programming. I am trying to read response from url and insert it into database. I ran my program which is posted below and it came back with this error:

Exception in thread "main" java.lang.NullPointerException
                       at javaapp.JavaApplication1.parseResponseString(JavaApplication1.java:41)
                       at javaapp.JavaApplication1.main(JavaApplication1.java:71)

I have been trying to solve this issue on my own through research, but I could not solve it. I was wondering if anyone can help me. If you do need any other information about my program, please just ask. Thanks in advance!

here is the code i have written

package javaapp;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;

public class JavaApplication1 
{

Map<String,String> responseMap=new HashMap<String, String>();
    static String input;

    public void getResponseFromUrl() throws IOException
    {
        URL url = new URL("http://localhost:8084/home/Home");
        HttpURLConnection con = (HttpURLConnection) url.openConnection();

        BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream())) ;
       String inputLine;
        while ((inputLine = in.readLine()) != null) 
        {
           if (inputLine.contains("<h1>")) 
            {
                String input = inputLine;
                input = input.substring(input.indexOf("<h1>") + 4, input.indexOf("</h1>"));   
            }
        }

    }
    public void parseResponseString(String input)
    {
        String params[]=input.split(",");

        for(String param:params)
        {
            String key= param.substring(0,param.indexOf('='));
            String value= param.substring(param.indexOf('=')+1,param.length());
            responseMap.put(key, value);
            System.out.println(param);
        }
    }
    public void insertToDatabase() throws SQLException, ClassNotFoundException
    {
        Connection conn=null;
        Class.forName("oracle.jdbc.driver.OracleDriver");

        conn=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:xe","jai","jaikiran");
        String insertQuery = " INSERT INTO value_1 (username1,username2,username3,username4,username5) "+
                             " values (?,?,?,?,?)";
        PreparedStatement pstmt = conn.prepareStatement(insertQuery);
        pstmt.setString(1,responseMap.get("username1"));
        pstmt.setString(2,responseMap.get("username2"));
        pstmt.setString(3,responseMap.get("username3"));
        pstmt.setString(4,responseMap.get("username4"));
        pstmt.setString(5,responseMap.get("username5"));
        pstmt.executeUpdate();
    }
    public static void main(String[] args) throws MalformedURLException, IOException, SQLException, ClassNotFoundException 
    {
        JavaApplication1 application =new JavaApplication1();
        application.getResponseFromUrl();
        application.parseResponseString(input);//shows exception here
        try {
            application.insertToDatabase();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }   
}

[Maneesh Godbole]

In future, while posting code, please UseCodeTags
I have added them this time for you. As you can see the tags make the code much more easier to read and understand

[Maneesh Godbole]

The stack trace is telling you what is gone wrong

                       at javaapp.JavaApplication1.parseResponseString(JavaApplication1.java:41)  

JavaApplication Line 41 is

       String params[]=input.split(",");  

So the variable "input" is null.

[James Boswell]

At this point in the code:

application.parseResponseString(input);

the static variable input is null. When passed to the parseResponseString method, the NullPointerException is thrown on the line:

String params[]=input.split(",");

because input is null.

From looking at the whole class, I think you think you are setting the input variable here:

while ((inputLine = in.readLine()) != null)   
        {  
           if (inputLine.contains("<h1>"))   
            {  
                String input = inputLine;  
                input = input.substring(input.indexOf("<h1>") + 4, input.indexOf("</h1>"));     
            }  
        }

But you are not as you had declared a local variable called input on line 5 of the snippet above. This is used and then discarded once this method completes.

[Jaikiran mathukumalli]

thanks a lot it helped but now i am getting new errors,sorry but i really am new to java please help

java.sql.SQLException: Listener refused the connection with the following error:
ORA-12505, TNS:listener does not currently know of SID given in connect descriptor

at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:419)
at oracle.jdbc.driver.PhysicalConnection.<init>(PhysicalConnection.java:536)
at oracle.jdbc.driver.T4CConnection.<init>(T4CConnection.java:228)
at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:32)
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:521)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at javaapp.JavaApplication1.insertToDatabase(JavaApplication1.java:61)
at javaapp.JavaApplication1.main(JavaApplication1.java:78)
Caused by: oracle.net.ns.NetException: Listener refused the connection with the following error:
ORA-12505, TNS:listener does not currently know of SID given in connect descriptor

at oracle.net.ns.NSProtocol.connect(NSProtocol.java:386)
at oracle.jdbc.driver.T4CConnection.connect(T4CConnection.java:1054)
at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:308)
... 8 more

[James Boswell]

Do you have Oracle installed correctly on the same machine?

If so, go to the command line and type the following:

tnsping xe

What output do you get?

[Doug Slavens]

// try changing line 33 from this:
String input = inputLine; 

// to this:
input = inputLine;