diff --git a/modules/swagger-parser-v3/src/main/java/io/swagger/v3/parser/processors/ExternalRefProcessor.java b/modules/swagger-parser-v3/src/main/java/io/swagger/v3/parser/processors/ExternalRefProcessor.java
index 4217f72263..8f9c92c77e 100644
--- a/modules/swagger-parser-v3/src/main/java/io/swagger/v3/parser/processors/ExternalRefProcessor.java
+++ b/modules/swagger-parser-v3/src/main/java/io/swagger/v3/parser/processors/ExternalRefProcessor.java
@@ -252,22 +252,24 @@ private void processSchema(Schema property, String file) {
             }
             if (property instanceof ComposedSchema) {
                 ComposedSchema composed = (ComposedSchema) property;
-                final Map<String, String> refMap = Optional.ofNullable(property.getDiscriminator())
+                final Map<String, String> refMap = Optional.ofNullable(composed.getDiscriminator())
                                 .map(Discriminator::getMapping).orElse(Collections.emptyMap()).entrySet()
                                 .stream().collect(Collectors.toMap(Map.Entry::getValue, Map.Entry::getKey));
                 Map<String, Schema> refCache = (!refMap.isEmpty() &&
-                        (property.getAnyOf() != null || property.getOneOf() != null)) ?
-                    ((List<Schema>)(property.getAnyOf() != null ? property.getAnyOf()
-                            : property.getOneOf())).stream()
+                        (composed.getAnyOf() != null || composed.getOneOf() != null)) ? Stream.of(
+                                composed.getAnyOf(), composed.getOneOf()
+                        )
+                            .filter(Objects::nonNull)
+                            .filter(l -> !l.isEmpty())
+                            .flatMap(Collection::stream)
                             .filter(s -> s.get$ref() != null)
-                            .collect(Collectors.toMap(Schema::get$ref, Function.identity())) : null;
+                            .collect(Collectors.toMap(Schema::get$ref, Function.identity())) : Collections.emptyMap();
 
                 processProperties(composed.getAllOf(), file);
                 processProperties(composed.getAnyOf(), file);
                 processProperties(composed.getOneOf(), file);
 
-                if (!refMap.isEmpty() && !refCache.isEmpty() &&
-                        (property.getAnyOf() != null || property.getOneOf() != null)) {
+                if (!refMap.isEmpty() && !refCache.isEmpty()) {
                     refCache.entrySet()
                             .stream().filter(e -> !e.getKey().equals(e.getValue().get$ref()))
                             .forEach(entry -> {
diff --git a/modules/swagger-parser-v3/src/main/java/io/swagger/v3/parser/processors/PathsProcessor.java b/modules/swagger-parser-v3/src/main/java/io/swagger/v3/parser/processors/PathsProcessor.java
index bd16ba580c..94cecd6754 100644
--- a/modules/swagger-parser-v3/src/main/java/io/swagger/v3/parser/processors/PathsProcessor.java
+++ b/modules/swagger-parser-v3/src/main/java/io/swagger/v3/parser/processors/PathsProcessor.java
@@ -19,9 +19,12 @@
 import io.swagger.v3.parser.models.RefFormat;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
+import java.util.stream.Stream;
 
 import static io.swagger.v3.parser.util.RefUtils.computeRefFormat;
 import static io.swagger.v3.parser.util.RefUtils.isAnExternalRefFormat;
@@ -265,15 +268,17 @@ else if(model instanceof ComposedSchema) {
                 // Map to cache old - new refs in composed schemas
                 Map<String, String> refMappings = composedSchema.getDiscriminator() != null &&
                         composedSchema.getDiscriminator().getMapping() != null ? new HashMap<>() : null;
-                List<Schema> schemas = composedSchema.getAnyOf() != null ? composedSchema.getAnyOf()
-                        : composedSchema.getOneOf();
-                for (Schema innerModel : schemas) {
-                    String oldRef = innerModel.get$ref();
-                    updateRefs(innerModel, pathRef);
-                    if(oldRef != null && refMappings != null && !oldRef.equals(innerModel.get$ref())) {
-                        refMappings.put(oldRef, innerModel.get$ref());
-                    }
-                }
+
+                Stream.of(composedSchema.getAnyOf(), composedSchema.getOneOf())
+                        .filter(Objects::nonNull).filter(l -> !l.isEmpty())
+                        .flatMap(Collection::stream)
+                        .forEach(innerModel -> {
+                            String oldRef = innerModel.get$ref();
+                            updateRefs(innerModel, pathRef);
+                            if(oldRef != null && refMappings != null && !oldRef.equals(innerModel.get$ref())) {
+                                refMappings.put(oldRef, innerModel.get$ref());
+                            }
+                });
                 // Update refs in discriminator mappings
                 if(refMappings != null && !refMappings.isEmpty()) {
                     Map<String, String> discriminatorMappings = composedSchema.getDiscriminator().getMapping();
diff --git a/modules/swagger-parser-v3/src/main/java/io/swagger/v3/parser/processors/SchemaProcessor.java b/modules/swagger-parser-v3/src/main/java/io/swagger/v3/parser/processors/SchemaProcessor.java
index c45ff8296d..9e6e7fafb2 100644
--- a/modules/swagger-parser-v3/src/main/java/io/swagger/v3/parser/processors/SchemaProcessor.java
+++ b/modules/swagger-parser-v3/src/main/java/io/swagger/v3/parser/processors/SchemaProcessor.java
@@ -14,9 +14,12 @@
 import io.swagger.v3.parser.util.OpenAPIDeserializer;
 import io.swagger.v3.parser.util.RefUtils;
 
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
+import java.util.stream.Stream;
 
 import static io.swagger.v3.parser.util.RefUtils.computeRefFormat;
 import static io.swagger.v3.parser.util.RefUtils.isAnExternalRefFormat;
@@ -158,21 +161,19 @@ public void processComposedSchema(ComposedSchema composedSchema) {
                 }
             }
         }
-        if(composedSchema.getOneOf() != null || composedSchema.getAnyOf() != null){
-            final List<Schema> schemas = composedSchema.getOneOf() != null ?
-                    composedSchema.getOneOf() : composedSchema.getAnyOf();
-            if (schemas != null) {
-                for (Schema schema : schemas) {
-                    if (schema.get$ref() != null) {
-                        String oldRef = schema.get$ref();
-                        processReferenceSchema(schema);
-                        String newRef = schema.get$ref();
-                        changeDiscriminatorMapping(composedSchema, oldRef, newRef);
-                    } else {
-                        processSchemaType(schema);
-                    }
-                }
-            }
+        if(composedSchema.getOneOf() != null || composedSchema.getAnyOf() != null) {
+            Stream.of(composedSchema.getOneOf(), composedSchema.getAnyOf())
+                    .filter(Objects::nonNull).filter(l -> !l.isEmpty()).flatMap(Collection::stream)
+                    .forEach(schema -> {
+                        if (schema.get$ref() != null) {
+                            String oldRef = schema.get$ref();
+                            processReferenceSchema(schema);
+                            String newRef = schema.get$ref();
+                            changeDiscriminatorMapping(composedSchema, oldRef, newRef);
+                        } else {
+                            processSchemaType(schema);
+                        }
+                    });
         }
     }