public void setGroups(java.util.Collection<ReservationCoverageGroup> groups) {
        if (groups == null) {
            this.groups = null;
            return;
        }

        this.groups = new java.util.ArrayList<ReservationCoverageGroup>(groups);
    }
<p>
The groups of instances that the reservation covered.
</p>

@param groups
       The groups of instances that the reservation covered.
aws-java-sdk-costexplorer/src/main/java/com/amazonaws/services/costexplorer/model/CoverageByTime.java