unable to call stored procedre from jdbc

Question

below is my JDBC code for connecting to DB and call a stored porcedure. i have installed the sqljdbc4v in src folder onf my project and the class path is also set to my bin folder and src folder.

Connection con = null;
    CallableStatement proc_stmt = null;
    ResultSet rs = null;

    try {

        Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");

        con = DriverManager.getConnection("jdbc:sqlserver://MYSERVER;databaseName=MYDATABASE", "USERID", "PASSWORD");

        proc_stmt = con.prepareCall("{ call generateID(?) }");

        proc_stmt.setString(1, "employee");
        rs = proc_stmt.executeQuery();

        if (rs.next()) {
            int employeeId = rs.getInt(1);
            System.out.println("Generated employeeId: " + employeeId);
        } else {
            System.out.println("Stored procedure couldn't generate new Id");
        }
    } catch (ClassNotFoundException ex) {
        ex.printStackTrace();
    } catch (SQLException ex) {
        ex.printStackTrace();
    } finally {

        try {

            rs.close();
            proc_stmt.close();
            con.close();

        } catch (SQLException ex) {
            ex.printStackTrace();
        }

    }

i keep on getting the below error

java.lang.ClassNotFoundException: com.microsoft.sqlserver.jdbc.SQLServerDriver
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Unknown Source)
    at StoredProcedure1.main(StoredProcedure1.java:18)
Exception in thread "main" java.lang.NullPointerException
    at StoredProcedure1.main(StoredProcedure1.java:41)

please help..