I'm trying to display a report in my src/iReport/report1.jasper directory. but every time i try to display it i get java.lang.NullPointerException. I can't find where the problem is. Please someone just take a look and help me. I have imported all necessary libraries. im using Netbeans.

package Windows;
import java.awt.Dimension;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import javax.swing.JFrame;
import net.sf.jasperreports.engine.JRException;
import net.sf.jasperreports.engine.JasperFillManager;
import net.sf.jasperreports.engine.JasperPrint;
import net.sf.jasperreports.swing.JRViewer;

public class Report1 extends javax.swing.JFrame {

    Connection conn = null;

    public void initConnection(){
        String HOST = "jdbc:mysql://localhost:3306/StudentDB";
        String USERNAME = "root";
        String PASSWORD = "";
        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException ex) {
            ex.printStackTrace();
        }

        try {
            conn = DriverManager.getConnection(HOST, USERNAME, PASSWORD);
        } catch (SQLException ex) {
            ex.printStackTrace();
        }
    }

     public void showReport(){

        //Path to your .jasper file in your package
        String reportName = "iReports\report1.jasper";
        //Get a stream to read the file
        InputStream is = this.getClass().getClassLoader().getResourceAsStream(reportName);
        try {
	 //Fill the report with parameter, connection and the stream reader
            JasperPrint jp = JasperFillManager.fillReport(is, null, conn);
  	 //Viewer for JasperReport
            JRViewer jv = new JRViewer(jp);
	 //Insert viewer to a JFrame to make it showable
            JFrame jf = new JFrame();
            jf.getContentPane().add(jv);
            jf.validate();
            jf.setVisible(true);
            jf.setSize(new Dimension(800,600));
            jf.setLocation(300,100);
            jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        } catch (JRException ex) {
            ex.printStackTrace();
        }
    }
    /** Creates new form Report1 */
    public Report1() {
        initComponents();
    }
    
    
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {

        jButton1 = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jButton1.setText("jButton1");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addComponent(jButton1)
                .addContainerGap(327, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addComponent(jButton1)
                .addContainerGap(277, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
        initConnection();
        showReport();
    }

    /**
    * @param args the command line arguments
    */
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new Report1().setVisible(true);
            }
        });


    }

    // Variables declaration - do not modify
    private javax.swing.JButton jButton1;
    // End of variables declaration

}

Paste us the error message.

I had to add Groove library to the project. Problem solved!

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