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). If the
date isn't provided, it's the first day of the current month. Dates can't be before the previous twelve months,
or in the future.
</p>

@return The Cost Category's effective start date. It can only be a billing start date (first day of the month).
        If the date isn't provided, it's the first day of the current month. Dates can't be before the previous
        twelve months, or in the future.
aws-java-sdk-costexplorer/src/main/java/com/amazonaws/services/costexplorer/model/UpdateCostCategoryDefinitionRequest.java