public java.util.List<String> getUserIds() {
        if (userIds == null) {
            userIds = new com.amazonaws.internal.SdkInternalList<String>();
        }
        return 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>

@return 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