Exception in thread main
java.lang.ClassFormatError: org.firebirdsq.jdbc.FBDriver
	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:620)
	at memprg.MyLoader.loadClass(MyLoader.java:174)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
	at memprg.MyLoader.main(MyLoader.java:193)

public class MyLoader extends ClassLoader
 

{

 Hashtable cache = new Hashtable();

    public PermissionCollection getPermissions(CodeSource codesource)
    {
        return _perm_collection;
    }

      private PermissionCollection _perm_collection;

    public MyLoader(ClassLoader parent)
    {
        
        super(parent);
            _perm_collection = getClass().getProtectionDomain().getPermissions();
    
    }

    public Object create_object(String class_name)
    {
        Class c;
        try
        {
            c = loadClass(class_name);
        }
        catch (ClassNotFoundException e)
        {
            return null;
        }

        try
        {
            return c.newInstance();
        }
        catch (IllegalAccessException e)
        {
            return null;
        }
        catch (InstantiationException e)
        {
            return null;
        }
    }


    public Object invoke_method(Object obj, String name, Object[] params, Class[] classes) throws Exception
    {
       String class_name = obj.getClass().getName();

        Method m = null;
        try
        {
            m = obj.getClass().getMethod(name, classes);
        }
        catch (NoSuchMethodException e)
        {
            throw new Exception("Error");
        }

        m.setAccessible(true);
        int mods = m.getModifiers();
        if (!Modifier.isPublic(mods))
        {
            throw new Exception("Error");
        }

        try
        {
            return m.invoke(obj, params);
        }
        catch (InvocationTargetException e)
        {
            throw new Exception("Error");
        }
        catch (IllegalAccessException e)
        {
            throw new Exception("Error");
        }
    }
    
    
    private byte loadClassData(String name)[] {
        String ourl = "jdbc:oracle:thin:@//myorcl:1521/orcl";
        Connection ocon = null;   
        byte bt[] = null;
        try{
            String odriver = "oracle.jdbc.OracleDriver";
            Class.forName(odriver).newInstance();
            //пользователь
            ocon = DriverManager.getConnection(ourl, "scott", "tiger");
          
         
           Statement select1 = ocon.createStatement();
           
            ResultSet rs1 = select1
                .executeQuery("select nfile,tg from file_dir where tg=0");
               while (rs1.next()){
                   System.out.println(rs1.getInt(2));
                 }   
               
        }catch(Exception ex){ }        
        
        
        return bt;
    }    
 

    public Class<?> loadClass(String name,boolean resolve) {
               
                 Class c = (Class)cache.get(name);
                 System.out.println(name);                          
                 
                 if (c == null) {
                     byte data[] = loadClassData(name);
                     System.out.println(data.length);
                     c = defineClass(name,data,0, data.length,null);
                    
                     cache.put(name, c);
                 }
                 if (resolve)
                     resolveClass(c);
                 return c;
             }
       
   
    public static void main(String[] args){
        String url = "jdbc:firebirdsql://168.3.5.93:3050/c:\\fb\\fb.fdb?user=user&password=password";
            try{  
            
            MyLoader ld = new MyLoader(ClassLoader.getSystemClassLoader());
                     
              Driver drv = (Driver)ld.loadClass("org.firebirdsq.jdbc.FBDriver").newInstance();
             Connection con = drv.connect(url,null);
             DriverManager.registerDriver(drv);   
              
             Statement select = con.createStatement(); 
            //Проверяем запрос
            ResultSet rs = select
               .executeQuery("select id from table where d in (5,10)");
            while (rs.next()){            
             
             int ow_id = rs.getInt(1);
             
             System.out.println(d+"!!");
             }
             
             rs.close();
    
             
          }catch(Exception e){
             
        }
       }    
    
}