Startup Script for Instance

Hello,
I'm trying to create an instance with startup script. I saw [ComputeExample.java](https://github.com/GoogleCloudPlatform/gcloud-java/blob/master/gcloud-java-examples/src/main/java/com/google/cloud/examples/compute/ComputeExample.java) but it describes process how to specify metadata for created instance.
How can I correctly specify startup script when create it?
