Details
Critical Description
Following is how OfficeToHtmlTransformer component is defined:
<component>
<role>org.xwiki.officeimporter.transformer.DocumentTransformer</role>
<role-hint>officetohtml</role-hint>
<implementation>org.xwiki.officeimporter.internal.transformer.OfficeToHtmlTransformer
</implementation>
<configuration>
<openOfficeServerIp>127.0.0.1</openOfficeServerIp>
<openOfficeServerPort>8100</openOfficeServerPort>
</configuration>
<instantiation-strategy>singleton</instantiation-strategy>
</component>
As you can see it's defined as a singleton. But this class itself contains state information particular to a specific import operation like temporary files and directories. This can cause havoc if the office importer is used simultaneously by many users.