public java.util.List<Configuration> getConfigurations() {
        if (configurations == null) {
            configurations = new com.amazonaws.internal.SdkInternalList<Configuration>();
        }
        return configurations;
    }
<note>
<p>
Amazon EMR releases 4.x or later.
</p>
</note>
<p>
The list of configurations supplied for an Amazon EMR cluster instance group. You can specify a separate
configuration for each instance group (master, core, and task).
</p>

@return <p>
        Amazon EMR releases 4.x or later.
        </p>
        </note>
        <p>
        The list of configurations supplied for an Amazon EMR cluster instance group. You can specify a separate
        configuration for each instance group (master, core, and task).
aws-java-sdk-emr/src/main/java/com/amazonaws/services/elasticmapreduce/model/InstanceGroup.java