Do not rely completely on the "Show Usages" feature of JDeveloper 11g

JDeveloper 11g has a nice ability in that when you delete a file, it can identify and determine whether this file is used anywhere else in the project.

Simply right-click on your file, click "Delete", and you will be prompted with the following:

 

The problem is that this check is not entirely exhaustive. For example, in your SOA code, it will not check if your file is being used inside an XPath function, as shown in the BPEL file below:

<assign name="SetOutput">
  <copy>
    <from expression="ora:processXSLT('Transformation_2.xsl',bpws:getVariableData('OutputMappingVariable'))"/>

    <to variable="outputVariable" part="payload"/>

  </copy>

</assign>

Therefore, be cautious when relying on the "Show Usages" feature in JDeveloper 11g.