diff --git a/src/main/java/be/ugent/rml/MappingOptimizer.java b/src/main/java/be/ugent/rml/MappingOptimizer.java
index 70be3760..3b4b9ac2 100644
--- a/src/main/java/be/ugent/rml/MappingOptimizer.java
+++ b/src/main/java/be/ugent/rml/MappingOptimizer.java
@@ -64,88 +64,94 @@ private void eliminateSelfJoins() {
         for (Quad refObjectMapQuad : refObjectMapsQuads) {
             Term parentTriplesMap = refObjectMapQuad.getObject();
             Term childObjectMap = refObjectMapQuad.getSubject();
-            Term parentLogicalSource = Utils.getObjectsFromQuads(rmlStore.getQuads(parentTriplesMap, new NamedNode(NAMESPACES.RML2 + "logicalSource"), null)).get(0);
-            Term childPredicateObjectMap = Utils.getSubjectsFromQuads(rmlStore.getQuads(null, new NamedNode(NAMESPACES.RML2 + "objectMap"), childObjectMap)).get(0);
-            Term childTriplesMap = Utils.getSubjectsFromQuads(rmlStore.getQuads(null, new NamedNode(NAMESPACES.RML2 + "predicateObjectMap"), childPredicateObjectMap)).get(0);
-            Term childLogicalSource = Utils.getObjectsFromQuads(rmlStore.getQuads(childTriplesMap, new NamedNode(NAMESPACES.RML2 + "logicalSource"), null)).get(0);
 
-            // check if the logical sources are the same
-            if (childLogicalSource.equals(parentLogicalSource)) {
 
-                List<Term> joinConditions = Utils.getObjectsFromQuads(rmlStore.getQuads(childObjectMap, new NamedNode(NAMESPACES.RML2 + "joinCondition"), null));
+            try {
+                Term parentLogicalSource = Utils.getObjectsFromQuads(rmlStore.getQuads(parentTriplesMap, new NamedNode(NAMESPACES.RML2 + "logicalSource"), null)).get(0);
+                Term childPredicateObjectMap = Utils.getSubjectsFromQuads(rmlStore.getQuads(null, new NamedNode(NAMESPACES.RML2 + "objectMap"), childObjectMap)).get(0);
+                Term childTriplesMap = Utils.getSubjectsFromQuads(rmlStore.getQuads(null, new NamedNode(NAMESPACES.RML2 + "predicateObjectMap"), childPredicateObjectMap)).get(0);
+                Term childLogicalSource = Utils.getObjectsFromQuads(rmlStore.getQuads(childTriplesMap, new NamedNode(NAMESPACES.RML2 + "logicalSource"), null)).get(0);
 
-                List<Term> parentSubjectMaps = Utils.getObjectsFromQuads(rmlStore.getQuads(parentTriplesMap, new NamedNode(NAMESPACES.RML2 + "subjectMap"), null));
-                 Term parentSubjectMap = null;
-                if (!parentSubjectMaps.isEmpty()) {
-                    parentSubjectMap = parentSubjectMaps.get(0);
-                }
+                // check if the logical sources are the same
+                if (childLogicalSource.equals(parentLogicalSource)) {
 
-                boolean safeSelfJoinElimination = true;
-
-                // if no join condition, we can safely eliminate the self-join
-                // else we need more checks
-                if (parentSubjectMap != null && !joinConditions.isEmpty()) {
-                    // we can eliminate a self-join when all join conditions have equal references and all references for the parent subject or all reference for the related child triple come back in the join conditions
-                    // 1. check if all join references are equal
-                    List<String> joinReferences = new ArrayList<>();
-                    for (Term joinCondition : joinConditions) {
-                        String parent = getObjectsFromQuads(rmlStore.getQuads(joinCondition, new NamedNode(NAMESPACES.RML2 + "parent"), null)).get(0).getValue();
-                        String child = getObjectsFromQuads(rmlStore.getQuads(joinCondition, new NamedNode(NAMESPACES.RML2 + "child"), null)).get(0).getValue();
-                        if (child.equals(parent)) {
-                            joinReferences.add(child);
-                        } else {
-                            safeSelfJoinElimination = false;
-                        }
+                    List<Term> joinConditions = Utils.getObjectsFromQuads(rmlStore.getQuads(childObjectMap, new NamedNode(NAMESPACES.RML2 + "joinCondition"), null));
+
+                    List<Term> parentSubjectMaps = Utils.getObjectsFromQuads(rmlStore.getQuads(parentTriplesMap, new NamedNode(NAMESPACES.RML2 + "subjectMap"), null));
+                    Term parentSubjectMap = null;
+                    if (!parentSubjectMaps.isEmpty()) {
+                        parentSubjectMap = parentSubjectMaps.get(0);
                     }
-                    if (safeSelfJoinElimination) {
-                        // 2. check if all references for the parent subject come back in the join conditions
-                        boolean safeTerms = hasSafeReferences(parentSubjectMap, joinReferences);
-                        if(!safeTerms) {
-                            // if not all references for the parent subject come back in the join conditions,
-                            // 3. check if all references for the related child terms come back in the join conditions
-                            // 3.1 check child subject
-                            List<Term> childSubjectMaps = Utils.getObjectsFromQuads(rmlStore.getQuads(parentTriplesMap, new NamedNode(NAMESPACES.RML2 + "subjectMap"), null));
-                            if(!childSubjectMaps.isEmpty()) {
-                                safeTerms = hasSafeReferences(childSubjectMaps.get(0), joinReferences);
+
+                    boolean safeSelfJoinElimination = true;
+
+                    // if no join condition, we can safely eliminate the self-join
+                    // else we need more checks
+                    if (parentSubjectMap != null && !joinConditions.isEmpty()) {
+                        // we can eliminate a self-join when all join conditions have equal references and all references for the parent subject or all reference for the related child triple come back in the join conditions
+                        // 1. check if all join references are equal
+                        List<String> joinReferences = new ArrayList<>();
+                        for (Term joinCondition : joinConditions) {
+                            String parent = getObjectsFromQuads(rmlStore.getQuads(joinCondition, new NamedNode(NAMESPACES.RML2 + "parent"), null)).get(0).getValue();
+                            String child = getObjectsFromQuads(rmlStore.getQuads(joinCondition, new NamedNode(NAMESPACES.RML2 + "child"), null)).get(0).getValue();
+                            if (child.equals(parent)) {
+                                joinReferences.add(child);
                             } else {
-                                safeTerms = true;
+                                safeSelfJoinElimination = false;
                             }
-                            //3.2 check child predicate (only make sense if the child subject was safe, otherwise we cannot eliminate the-self join)
-                            if (safeTerms) {
-                                List<Term> childPredicateMaps = Utils.getObjectsFromQuads(rmlStore.getQuads(childPredicateObjectMap, new NamedNode(NAMESPACES.RML2 + "predicateMap"), null));
-                                if(!childPredicateMaps.isEmpty()) {
-                                    safeTerms = hasSafeReferences(childPredicateMaps.get(0), joinReferences);
+                        }
+                        if (safeSelfJoinElimination) {
+                            // 2. check if all references for the parent subject come back in the join conditions
+                            boolean safeTerms = hasSafeReferences(parentSubjectMap, joinReferences);
+                            if (!safeTerms) {
+                                // if not all references for the parent subject come back in the join conditions,
+                                // 3. check if all references for the related child terms come back in the join conditions
+                                // 3.1 check child subject
+                                List<Term> childSubjectMaps = Utils.getObjectsFromQuads(rmlStore.getQuads(parentTriplesMap, new NamedNode(NAMESPACES.RML2 + "subjectMap"), null));
+                                if (!childSubjectMaps.isEmpty()) {
+                                    safeTerms = hasSafeReferences(childSubjectMaps.get(0), joinReferences);
+                                } else {
+                                    safeTerms = true;
+                                }
+                                //3.2 check child predicate (only make sense if the child subject was safe, otherwise we cannot eliminate the-self join)
+                                if (safeTerms) {
+                                    List<Term> childPredicateMaps = Utils.getObjectsFromQuads(rmlStore.getQuads(childPredicateObjectMap, new NamedNode(NAMESPACES.RML2 + "predicateMap"), null));
+                                    if (!childPredicateMaps.isEmpty()) {
+                                        safeTerms = hasSafeReferences(childPredicateMaps.get(0), joinReferences);
+                                    }
                                 }
                             }
-                        }
-                        // 4. if parent subject or all child terms are safe, the self join can be eliminated, else not
-                        if (!safeTerms) {
-                            safeSelfJoinElimination = false;
+                            // 4. if parent subject or all child terms are safe, the self join can be eliminated, else not
+                            if (!safeTerms) {
+                                safeSelfJoinElimination = false;
+                            }
                         }
                     }
-                }
-                if (safeSelfJoinElimination) {
-                    // now we rewrite the mapping file to eliminate the self-join
-                    boolean termTypeAdded = false;
-                    List<Quad> parentSubjectMapQuads = rmlStore.getQuads(parentSubjectMap, null, null);
-                    for (Quad parentSubjectMapQuad : parentSubjectMapQuads) {
-                        Term predicate = parentSubjectMapQuad.getPredicate();
-                        if (predicate.equals(new NamedNode(NAMESPACES.FNML + "functionValue"))
-                                || predicate.equals(new NamedNode(NAMESPACES.RML2 + "termType"))
-                                || predicate.equals(new NamedNode(NAMESPACES.RML2 + "reference"))
-                                || predicate.equals(new NamedNode(NAMESPACES.RML2 + "template"))
-                                || predicate.equals(new NamedNode(NAMESPACES.RML2 + "constant"))) {
-                            rmlStore.addQuad(childObjectMap, predicate, parentSubjectMapQuad.getObject());
+                    if (safeSelfJoinElimination) {
+                        // now we rewrite the mapping file to eliminate the self-join
+                        boolean termTypeAdded = false;
+                        List<Quad> parentSubjectMapQuads = rmlStore.getQuads(parentSubjectMap, null, null);
+                        for (Quad parentSubjectMapQuad : parentSubjectMapQuads) {
+                            Term predicate = parentSubjectMapQuad.getPredicate();
+                            if (predicate.equals(new NamedNode(NAMESPACES.FNML + "functionValue"))
+                                    || predicate.equals(new NamedNode(NAMESPACES.RML2 + "termType"))
+                                    || predicate.equals(new NamedNode(NAMESPACES.RML2 + "reference"))
+                                    || predicate.equals(new NamedNode(NAMESPACES.RML2 + "template"))
+                                    || predicate.equals(new NamedNode(NAMESPACES.RML2 + "constant"))) {
+                                rmlStore.addQuad(childObjectMap, predicate, parentSubjectMapQuad.getObject());
+                            }
+                            if (predicate.equals(new NamedNode(NAMESPACES.RML2 + "termType"))) {
+                                termTypeAdded = true;
+                            }
                         }
-                        if (predicate.equals(new NamedNode(NAMESPACES.RML2 + "termType"))) {
-                            termTypeAdded = true;
+                        rmlStore.removeQuads(childObjectMap, new NamedNode(NAMESPACES.RML2 + "parentTriplesMap"), parentTriplesMap);
+                        if (!termTypeAdded) {
+                            rmlStore.addQuad(childObjectMap, new NamedNode(NAMESPACES.RML2 + "termType"), new NamedNode(NAMESPACES.RML2 + "IRI"));
                         }
                     }
-                    rmlStore.removeQuads(childObjectMap, new NamedNode(NAMESPACES.RML2 + "parentTriplesMap"), parentTriplesMap);
-                    if (!termTypeAdded) {
-                        rmlStore.addQuad(childObjectMap, new NamedNode(NAMESPACES.RML2 + "termType"), new NamedNode(NAMESPACES.RML2 + "IRI"));
-                    }
                 }
+            } catch (java.lang.IndexOutOfBoundsException e) {
+                continue;
             }
         }
     }
diff --git a/src/main/java/be/ugent/rml/records/RecordsFactory.java b/src/main/java/be/ugent/rml/records/RecordsFactory.java
index 69480fb1..a61bb6d2 100644
--- a/src/main/java/be/ugent/rml/records/RecordsFactory.java
+++ b/src/main/java/be/ugent/rml/records/RecordsFactory.java
@@ -73,7 +73,8 @@ public List<Record> createRecords(Term triplesMap, QuadStore rmlStore) throws Ex
 
             return getRecords(access, logicalSource, referenceFormulation, rmlStore);
         } else {
-            throw new Error("No Logical Source is found for " + triplesMap + ". Exactly one Logical Source is required per Triples Map.");
+            logger.error("No Logical Source is found for " + triplesMap + ". Exactly one Logical Source is required per Triples Map.");
+            return new ArrayList<>();
         }
     }