public void setAvailabilityZones(java.util.Collection<String> availabilityZones) {
        if (availabilityZones == null) {
            this.availabilityZones = null;
            return;
        }

        this.availabilityZones = new com.amazonaws.internal.SdkInternalList<String>(availabilityZones);
    }
<p>
When multiple Availability Zones are specified, Amazon EMR evaluates them and launches instances in the optimal
Availability Zone. <code>AvailabilityZones</code> is used for instance fleets, while
<code>AvailabilityZone</code> (singular) is used for uniform instance groups.
</p>
<note>
<p>
The instance fleet configuration is available only in Amazon EMR releases 4.8.0 and later, excluding 5.0.x
versions.
</p>
</note>

@param availabilityZones
       When multiple Availability Zones are specified, Amazon EMR evaluates them and launches instances in the
       optimal Availability Zone. <code>AvailabilityZones</code> is used for instance fleets, while
       <code>AvailabilityZone</code> (singular) is used for uniform instance groups.</p> <note>
       <p>
       The instance fleet configuration is available only in Amazon EMR releases 4.8.0 and later, excluding 5.0.x
       versions.
       </p>
aws-java-sdk-emr/src/main/java/com/amazonaws/services/elasticmapreduce/model/PlacementType.java