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

@param effectiveStart
       The Cost Category's effective start date. It can only be a billing start date (first day of the month).
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-costexplorer/src/main/java/com/amazonaws/services/costexplorer/model/UpdateCostCategoryDefinitionResult.java