What happens if I have same duplicate UUID in report?

In my jasper report, I am using elements something like this:

<textField isStretchWithOverflow="true">
    <reportElement style="alternateStyle" positionType="Float" stretchType="RelativeToTallestObject" x="292" y="0" width="85" height="30" uuid="b93b4e99-d6fb-4679-836d-9b198cb5fe1c"/>
    <textElement textAlignment="Center" verticalAlignment="Middle">
        <font fontName="SMCustomFont" size="9" isBold="false"/>
        <paragraph leftIndent="3"/>
    </textElement>
    <textFieldExpression><![CDATA[($F{SOMEEXP}]]></textFieldExpression>
</textField>

Here the uuid is "b93b4e99-d6fb-4679-836d-9b198cb5fe1c".

My question is What happens if I keep the UUID same for some other textField element in the same JRXML file and what is the significance of UUID?

When I tried, the report is generating fine.

Solution

Jasper reports use the UUID in the engine to identify elements, see for example SortElementJsonHandler.getCurrentSortField.

A Friendly User (staff) at the Jasper Community forum states

UUID is used mostly for the interactive elements like tables and crosstabs to identify the elements for sorting/filtering/etc. It's used in the viewer and on the engine level, I am not sure there is useful API available to interact with elements using UUID.

Also as far as I can see, in most simple cases like two textField there is no problem having same UUID, but you can get strange result if you have a more complex design with multiple similar components and all of them have same UUID

Use the IDE and you don't need to worry about it.

If you copy and past elements/components in the raw jrxml, either change a number or remove the UUID, when saved in JasperSoft Studio it will auto-generate it for you if it does not exists. Overall I would suggest that you use the IDE for all actions (copy and past etc), personally I only use the code/jrxml view if I need to do some quick replace of something etc.