public String getNamespace() {
        return this.namespace;
    }
<p>
If this metric definition is for a custom metric instead of an extended metric, this field displays the metric
namespace that the custom metric is published to.
</p>

@return If this metric definition is for a custom metric instead of an extended metric, this field displays the
        metric namespace that the custom metric is published to.
aws-java-sdk-cloudwatchrum/src/main/java/com/amazonaws/services/cloudwatchrum/model/MetricDefinition.java