public java.util.List<InstanceGroupDetail> getInstanceGroups() {
        if (instanceGroups == null) {
            instanceGroups = new com.amazonaws.internal.SdkInternalList<InstanceGroupDetail>();
        }
        return instanceGroups;
    }
<p>
Details about the instance groups in a cluster.
</p>

@return Details about the instance groups in a cluster.
aws-java-sdk-emr/src/main/java/com/amazonaws/services/elasticmapreduce/model/JobFlowInstancesDetail.java