qb-test.java, from http://www.molecularbear.com/blog/?p=60

qb-test.java

import com.jacob.com.*;

public class Foo {
  public static void main(String[] args) {
    System.out.println("Hello world!");
    // QBFC constants looked up using the object browser
    Variant ctLocalQDB = new Variant(1);
    Variant omDontCare = new Variant(2);
    // major and minor version of qbXML used to talk to QuickBooks
    Variant qbXMLMajor = new Variant(6);
    Variant qbXMLMinor = new Variant(0);
    // location of the company file to access
    String qbFile = "C:\\Documents and Settings\\rdavis\\Desktop\\FfAMETest.QBW";
    // connect to QuickBooks
    Dispatch qbsm = new Dispatch("QBFC7.QBSessionManager");
    Dispatch.call(qbsm, "OpenConnection2", "", "My Sample App", ctLocalQDB);
    Dispatch.call(qbsm, "BeginSession", qbFile, omDontCare);
    // build and execute a request to obtain all vendors
    Dispatch msgSet = Dispatch.call(qbsm, "CreateMsgSetRequest", "US", qbXMLMajor, qbXMLMinor).toDispatch();
    Dispatch.call(msgSet, "AppendVendorQueryRq");
    Dispatch resSet = Dispatch.call(qbsm, "DoRequests", msgSet).toDispatch();
    Dispatch resList = Dispatch.get(resSet, "ResponseList").toDispatch();
    int count = Dispatch.get(resList, "Count").getInt();
    for (int i = 0; i < count; i++) {
      Dispatch res = Dispatch.call(resList, "GetAt", new Variant(i)).toDispatch();
      // blindly assume that we have a vendor response
      Dispatch vendList = Dispatch.get(res, "Detail").toDispatch();
      int vcount = Dispatch.get(vendList, "Count").getInt();
      for (int j = 0; j < vcount; j++) {
        Dispatch vend = Dispatch.call(vendList, "GetAt", new Variant(j)).toDispatch();
        Dispatch dname = Dispatch.get(vend, "Name").toDispatch();
        String name = Dispatch.call(dname, "GetValue").getString();
        System.out.println("Vendor: " + name);
      }
    }
    // close the QuickBooks connection
    Dispatch.call(qbsm, "EndSession");
    Dispatch.call(qbsm, "CloseConnection");
    System.out.println("Goodbye world!");
  }
}

got error com.jacob.com.ComFailException: Can't co-create object