public void setGreKey(Integer greKey) {
        this.greKey = greKey;
    }
<p>
The application key when you use the GRE protocol.
</p>

@param greKey
       The application key when you use the GRE protocol.
aws-java-sdk-ec2/src/main/java/com/amazonaws/services/ec2/model/TrunkInterfaceAssociation.java