Hi, While trying to get some integration tests of the Maven Drools Plugin green when used with Drools 5.2.0.Final and 5.3.0.Beta1, I'm getting weird behaviour of the newer Drools version when it comes to deserializing KnowledgePackages. What do I do in the code? - compile three *.drl files (see below) - serialize the resulting KnowledgePackages using DroolsStreamUtils.streamOut(new FileOutputStream(outputFile), knowledgeBuilder.getKnowledgePackages(), false) from within the plugin (see [1], [2]) - de-serialize the knowledge packages using DroolsStreamUtils.streamIn(new FileInputStream(file)) in a TestNG test [3], using [4] - I get java.lang.ClassNotFoundException for a declared data type: java.lang.ClassNotFoundException: model.Age at java.net.URLClassLoader$1.run(URLClassLoader.java:202) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:190) at java.lang.ClassLoader.loadClass(ClassLoader.java:307) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:248) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:247) at org.drools.common.DroolsObjectInputStream.resolveClass(DroolsObjectInputStream.java:85) at org.drools.common.DroolsObjectInputStream.resolveClass(DroolsObjectInputStream.java:97) at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1574) at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1495) Strangely enough, the same code works well if I switch to Drools 5.1.1. What changed between 5.1.1 and 5.2.0.Final that might cause this effect? Might I be doing something wrong using DroolsStreamUtils? Would be happy about any hints. Thank you in advance. Here are the three input files, which get compiled exactly in this order: 1) Person.drl package model; declare Person name: String end 2) Age.drl package model; declare Age person: Person age: Integer end 3) minimum-age.drl: package rules; dialect "mvel" import model.Person; import model.Age; rule "check minimum age" when Age( $person: person, age < 18 ) then insertLogical("TOO YOUNG: " + $person.name ) end Best regards Ansgar [1] https://github.com/maven-drools/plugin.maven-drools-plugin/blob/57c77fce2... [2] https://github.com/maven-drools/plugin.maven-drools-plugin/blob/57c77fce2... [3] https://github.com/maven-drools/plugin.maven-drools-plugin/blob/57c77fce2... [4] https://github.com/maven-drools/plugin.knowledge-io/blob/a89bcf581d75b2ac...