private void jList1MouseClicked(java.awt.event.MouseEvent evt) {

        String labels[] = new String[10];
        int i=0;
        try{
            Class.forName("java.sql.Driver");
            Connection con=DriverManager.getConnection("jdbc:mysql://localhost/bookstore","root","root");
            Statement stmt = con.createStatement();
            String query="select category from inventorymain;";
            ResultSet rs=stmt.executeQuery(query);
            while(rs.next()){
                labels[i]=rs.getString("category");
                i++;
               //dlm.addElement(rs.getString("category"));
            }
            rs.close();
            stmt.close();
            con.close();
        }
        catch(Exception e1){
            e1.printStackTrace();
        }finally{
        }
       jList1.setListData(labels );
this get executed after i click on the jlist box
this is my jbutton code
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
String category=(String)jList1.getSelectedValue();
System.out.print(""+category);
}

this problem here is that always gives my selected value as null and selected index as -1 for all values
almost tried all solution on stackflow but not found any working for mine