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

@param greKey
       The application key when you use the GRE protocol.
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-ec2/src/main/java/com/amazonaws/services/ec2/model/TrunkInterfaceAssociation.java