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

        this.userIds = new com.amazonaws.internal.SdkInternalList<String>(userIds);
    }
<p>
The Amazon Web Services account IDs. This parameter can be used only when the <code>Attribute</code> parameter is
<code>launchPermission</code>.
</p>

@param userIds
       The Amazon Web Services account IDs. This parameter can be used only when the <code>Attribute</code>
       parameter is <code>launchPermission</code>.
aws-java-sdk-ec2/src/main/java/com/amazonaws/services/ec2/model/ModifyImageAttributeRequest.java