public void setCreationTimestamp(String creationTimestamp) {
        this.creationTimestamp = creationTimestamp;
    }
The time, in milliseconds since the epoch, when the core definition version was created.

@param creationTimestamp
       The time, in milliseconds since the epoch, when the core definition version was created.
aws-java-sdk-greengrass/src/main/java/com/amazonaws/services/greengrass/model/GetCoreDefinitionVersionResult.java