I meet working a simple example to interiorize with jboss rules and I obtain the following error: Exception in thread "main" org.drools.rule.InvalidRulePackage: Unable to create Field Extractor for 'CantSegundos' : [Rule name=Valida Duracion nula, agendaGroup=MAIN, salience=0, no-loop=false] *org.drools.RuntimeDroolsException* : *org.drools.RuntimeDroolsException *: java.lang.NullPointerExceptionUnable to create Field Extractor for 'CantSegundos' : [Rule name=valida Duracion , agendaGroup=MAIN, salience=0, no-loop=false]* org.drools.RuntimeDroolsException *: *org.drools.RuntimeDroolsException*: *java.lang.NullPointerException* at org.drools.rule.Package.checkValidity( *Package.java:408*) at org.drools.common.AbstractRuleBase.addPackage( *AbstractRuleBase.java:288*) at prototipo.Prueba.main( *Prueba.java:27*) the class main is: * public * *static* *final* *void* main(String[] args) *throws* Exception { * final* PackageBuilder builder = *new* PackageBuilder(); * *builder.addPackageFromDrl( *new* InputStreamReader( Prueba.*class *.getResourceAsStream( "regla.drl") ) ); * final* RuleBase ruleBase = RuleBaseFactory.*newRuleBase*(); * ruleBase*.addPackage( builder.getPackage() ); * final* StatefulSession session = ruleBase.newStatefulSession(); * *Integer segundos = *new* Integer(5); * *validaciones valida = *new* validaciones(); * *valida.setCantSegundos(segundos); * *session.insert( valida); * *session.fireAllRules(); *in the rules is:* * * *package* prototipo *import* prototipo.validaciones; *rule* "Valida Duracion nula" *when * v : validaciones(CantSegundos == 0) *then* v.setResultado( "I"); System.out.println( "obtenemos" + v.getResultado() ); *end **rule* "valida Duracion "* when * v : validaciones(CantSegundos > 0) *then* v.setResultado( "S"); System.out.println( "obtenemos" + v.getResultado()); *end** Thank you for helping me. *** ** _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users