Java Database Connectivity (JDBC)

Hi

I need to create a Clob variable that will be filled with some text. After that I will use this variable in a stored procedure.
I'm using the following code:

Connection conn = null;
Clob c = null;

conn = db.getConnection();
c = conn.createClob();

//c.setString(1, "text text text");



I'm getting java.lang.NullPointerException in this line c = conn.createClob();.
Anyone know what I'm doing wrong, or if there is another way to create a Clob variable?

Thanks in advance.
Luís Matos