public String getEffectiveStart() {
        return this.effectiveStart;
    }
<p>
The Cost Category's effective start date. It can only be a billing start date (first day of the month).
</p>

@return The Cost Category's effective start date. It can only be a billing start date (first day of the month).
aws-java-sdk-costexplorer/src/main/java/com/amazonaws/services/costexplorer/model/UpdateCostCategoryDefinitionResult.java