diff --git a/fusion-endpoint/pom.xml b/fusion-endpoint/pom.xml
index 71fe5b6e938..58378a6e9bb 100644
--- a/fusion-endpoint/pom.xml
+++ b/fusion-endpoint/pom.xml
@@ -17,7 +17,7 @@
         <spring.version>5.3.0</spring.version>
         <spring.autoconfigure.version>2.2.0.RELEASE</spring.autoconfigure.version>
         <javax.annotation.api.version>1.3.2</javax.annotation.api.version>
-        <javaparser.version>3.15.1</javaparser.version>
+        <javaparser.version>3.23.0</javaparser.version>
         <swagger.codegen.version>3.0.2</swagger.codegen.version>
         <swagger.codegen.generators.version>1.0.2</swagger.codegen.generators.version>
     </properties>
diff --git a/fusion-endpoint/src/main/java/com/vaadin/fusion/generator/OpenAPIObjectGenerator.java b/fusion-endpoint/src/main/java/com/vaadin/fusion/generator/OpenAPIObjectGenerator.java
index 42d9cc351bb..4d14aedc6ba 100644
--- a/fusion-endpoint/src/main/java/com/vaadin/fusion/generator/OpenAPIObjectGenerator.java
+++ b/fusion-endpoint/src/main/java/com/vaadin/fusion/generator/OpenAPIObjectGenerator.java
@@ -811,7 +811,8 @@ private List<Schema> parseReferencedTypeAsSchema(GeneratorType type) {
 
         List<ResolvedReferenceType> directAncestors = resolvedReferenceType
                 .getDirectAncestors().stream()
-                .filter(parent -> parent.getTypeDeclaration().isClass()
+                .filter(parent -> parent.getTypeDeclaration()
+                        .orElseThrow(IllegalArgumentException::new).isClass()
                         && !Object.class.getName()
                                 .equals(parent.getQualifiedName()))
                 .collect(Collectors.toList());
@@ -864,7 +865,8 @@ private List<Schema> generatedRelatedSchemas(Schema schema) {
      */
     private String getFullyQualifiedName(GeneratorType type) {
         ResolvedReferenceTypeDeclaration typeDeclaration = type.asResolvedType()
-                .asReferenceType().getTypeDeclaration();
+                .asReferenceType().getTypeDeclaration()
+                .orElseThrow(IllegalArgumentException::new);
         String packageName = typeDeclaration.getPackageName();
         String canonicalName = typeDeclaration.getQualifiedName();
         if (GeneratorUtils.isBlank(packageName)) {
diff --git a/fusion-endpoint/src/main/java/com/vaadin/fusion/generator/SchemaGenerator.java b/fusion-endpoint/src/main/java/com/vaadin/fusion/generator/SchemaGenerator.java
index f605b664d27..84f0208d8ce 100644
--- a/fusion-endpoint/src/main/java/com/vaadin/fusion/generator/SchemaGenerator.java
+++ b/fusion-endpoint/src/main/java/com/vaadin/fusion/generator/SchemaGenerator.java
@@ -35,6 +35,7 @@
 import com.github.javaparser.ast.type.Type;
 import com.github.javaparser.resolution.declarations.ResolvedEnumConstantDeclaration;
 import com.github.javaparser.resolution.declarations.ResolvedFieldDeclaration;
+import com.github.javaparser.resolution.declarations.ResolvedReferenceTypeDeclaration;
 import com.github.javaparser.resolution.types.ResolvedReferenceType;
 import com.github.javaparser.resolution.types.ResolvedType;
 
@@ -115,7 +116,8 @@ Schema createSingleSchemaFromResolvedType(GeneratorType type) {
 
         if (type.isEnum()) {
             List<String> entries = resolvedReferenceType.getTypeDeclaration()
-                    .asEnum().getEnumConstants().stream()
+                    .orElseThrow(IllegalArgumentException::new).asEnum()
+                    .getEnumConstants().stream()
                     .map(ResolvedEnumConstantDeclaration::getName)
                     .collect(Collectors.toList());
             StringSchema schema = new StringSchema();
@@ -127,7 +129,8 @@ Schema createSingleSchemaFromResolvedType(GeneratorType type) {
                 .name(resolvedReferenceType.getQualifiedName());
         Map<String, Boolean> fieldsOptionalMap = getFieldsAndOptionalMap(type);
         List<ResolvedFieldDeclaration> serializableFields = resolvedReferenceType
-                .getTypeDeclaration().getDeclaredFields().stream()
+                .getTypeDeclaration().orElseThrow(IllegalArgumentException::new)
+                .getDeclaredFields().stream()
                 .filter(resolvedFieldDeclaration -> fieldsOptionalMap
                         .containsKey(resolvedFieldDeclaration.getName()))
                 .collect(Collectors.toList());
@@ -167,9 +170,11 @@ private Map<String, Boolean> getFieldsAndOptionalMap(GeneratorType type) {
         ResolvedReferenceType resolvedReferenceType = type.asResolvedType()
                 .asReferenceType();
 
-        if (!resolvedReferenceType.getTypeDeclaration().isClass()
-                || resolvedReferenceType.getTypeDeclaration()
-                        .isAnonymousClass()) {
+        Optional<ResolvedReferenceTypeDeclaration> typeDeclaration = resolvedReferenceType
+                .getTypeDeclaration();
+        if (!typeDeclaration
+                .filter(td -> td.isClass() && !td.isAnonymousClass())
+                .isPresent()) {
             return Collections.emptyMap();
         }
         HashMap<String, Boolean> validFields = new HashMap<>();
diff --git a/fusion-endpoint/src/main/java/com/vaadin/fusion/generator/SchemaResolver.java b/fusion-endpoint/src/main/java/com/vaadin/fusion/generator/SchemaResolver.java
index f95be9f0a42..919a6736373 100644
--- a/fusion-endpoint/src/main/java/com/vaadin/fusion/generator/SchemaResolver.java
+++ b/fusion-endpoint/src/main/java/com/vaadin/fusion/generator/SchemaResolver.java
@@ -187,7 +187,8 @@ private Schema createEnumTypeSchema() {
         ResolvedReferenceType resolvedReferenceType = type.asResolvedType()
                 .asReferenceType();
         List<String> entries = resolvedReferenceType.getTypeDeclaration()
-                .asEnum().getEnumConstants().stream()
+                .orElseThrow(IllegalArgumentException::new).asEnum()
+                .getEnumConstants().stream()
                 .map(ResolvedEnumConstantDeclaration::getName)
                 .collect(Collectors.toList());
         String qualifiedName = resolvedReferenceType.getQualifiedName();