public java.util.List<VpcSecurityGroupMembership> getVpcSecurityGroups() {
        if (vpcSecurityGroups == null) {
            vpcSecurityGroups = new com.amazonaws.internal.SdkInternalList<VpcSecurityGroupMembership>();
        }
        return vpcSecurityGroups;
    }
<p>
A list of Amazon Virtual Private Cloud (Amazon VPC) security groups that are associated with the cluster. This
parameter is returned only if the cluster is in a VPC.
</p>

@return A list of Amazon Virtual Private Cloud (Amazon VPC) security groups that are associated with the cluster.
        This parameter is returned only if the cluster is in a VPC.
aws-java-sdk-redshift/src/main/java/com/amazonaws/services/redshift/model/Cluster.java