1) Checkout https://github.com/mff-uk/DPUs/tree/master/, build uk-version-adapter

2) Put uk-version-adapter JAR file among libs, thus it has to be copied to {module.path}/target/lib, where  {module.path} is the property in config.properties

3) adjust config.properties for frontend, set the property to module.frontend.expose: 

module.frontend.expose = sun.misc,sun.io,eu.unifiedviews.dpu;version="1.6.0",eu.unifiedviews.dpu.config;version="1.6.0",eu.unifiedviews.dataunit;uses:="org.openrdf.repository,org.openrdf.model";version="1.6.0",eu.unifiedviews.dataunit.rdf;uses:="org.openrdf.model,eu.unifiedviews.dataunit";version="1.6.0",eu.unifiedviews.dataunit.files;uses:="eu.unifiedviews.dataunit";version="1.6.0",eu.unifiedviews.dataunit.relational;uses:="eu.unifiedviews.dataunit,java.sql";version="1.6.0"

4) adjust config.properties for backend, set the property module.backend.expose to: 

module.backend.expose = sun.misc,sun.io,eu.unifiedviews.dpu;version="1.6.0",eu.unifiedviews.dpu.config;version="1.6.0",eu.unifiedviews.dataunit;uses:="org.openrdf.repository,org.openrdf.model";version="1.6.0",eu.unifiedviews.dataunit.rdf;uses:="org.openrdf.model,eu.unifiedviews.dataunit";version="1.6.0",eu.unifiedviews.dataunit.files;uses:="eu.unifiedviews.dataunit";version="1.6.0",eu.unifiedviews.dataunit.relational;uses:="eu.unifiedviews.dataunit,java.sql";version="1.6.0"

 

Explanation: As result of 2), lib is loaded by the backend/frontend and 3)4) ensures that all the needed classes for backward compatibility are available to DPUs