The exception is throw because your application can't find the Renjin ScriptEngine. You have provided renjin-studio as a library, but you need the renjin-script-engine library which is available from http://build.bedatadriven.com/job/renjin/lastSuccessfulBuild/org.renjin$renjin-script-engine/ (use the JAR with dependencies).
Unfortunately ScriptEngineManager.getEngineByName()
only returns null
if it can't find the engine so you can add the following check to ensure that the engine has loaded:
// check if the engine has loaded correctly:
if(engine == null) {
throw new RuntimeException("Renjin Script Engine not found on the classpath.");
}
Also note: it is called Renjin, not Rengin!