java.lang.NullPointerException: Cannot invoke method addURL() on null object

[Pria]

Below are the first few lines of my groovy file. When i try to run it from the server, i get the error java.lang.NullPointerException: Cannot invoke method addURL() on null object
        at org.codehaus.groovy.runtime.NullObject.invokeMethod(NullObject.java:77)

I am not sure how the code needs to be changed here to fix the above error:

package groovy;

def localFile = new File("/tmp/sqljdbc4.jar");
this.class.classLoader.rootLoader.addURL(localFile.toURI().toURL());

import java.sql.Connection;
import java.sql.DriverManager;
import com.microsoft.sqlserver.jdbc.*;
import groovy.sql.Sql;

Connection ret = null;

try {
SQLServerDataSource ds = new SQLServerDataSource()
......

Thanks

Pria

[Nic Brough -Adaptavist-]

What is on line 77 where the error happens?  There's an "addUrl" call on line 3, but we have no way of knowing that this is where the error really happens.

Please, give us the whole thing, NOT as a screenshot image, as those are useless for code, but the whole script (redact data if you need to, it's the structure and code we need)