Internal error in the mapping processor: java.lang.StackOverflowError

Question

While trying to map my domain objects I get the following StackOverflowError exception. I've tried to ignore the properties causing circular dependencies to no avail.

At the center of my domain model is the WorkoutSet which has a User and an Exercise.

If I remove the mapping annotation from the WorkoutSetMapper the UserMapperImpl and the ExerciseMapperImpl is generated as expected.

Error:(15, 1) java: Internal error in the mapping processor: java.lang.StackOverflowError at com.sun.tools.javac.code.Type$ClassType.accept(Type.java:786) at com.sun.tools.javac.code.Types$UnaryVisitor.visit(Types.java:4652) at com.sun.tools.javac.code.Types.supertype(Types.java:2315) at com.sun.tools.javac.code.Types$13.visitClassType(Types.java:1966) at com.sun.tools.javac.code.Types$13.visitClassType(Types.java:1955) at com.sun.tools.javac.code.Type$ClassType.accept(Type.java:786) at com.sun.tools.javac.code.Types$DefaultTypeVisitor.visit(Types.java:4571) at com.sun.tools.javac.code.Types.asSuper(Types.java:1952) at com.sun.tools.javac.code.Types$13.visitClassType(Types.java:1968) at com.sun.tools.javac.code.Types$13.visitClassType(Types.java:1955) at com.sun.tools.javac.code.Type$ClassType.accept(Type.java:786) at com.sun.tools.javac.code.Types$DefaultTypeVisitor.visit(Types.java:4571) at com.sun.tools.javac.code.Types.asSuper(Types.java:1952) at com.sun.tools.javac.code.Types$13.visitClassType(Types.java:1975) at com.sun.tools.javac.code.Types$13.visitClassType(Types.java:1955) at com.sun.tools.javac.code.Type$ClassType.accept(Type.java:786) at com.sun.tools.javac.code.Types$DefaultTypeVisitor.visit(Types.java:4571) at com.sun.tools.javac.code.Types.asSuper(Types.java:1952) at com.sun.tools.javac.code.Types$13.visitClassType(Types.java:1975) at com.sun.tools.javac.code.Types$13.visitClassType(Types.java:1955) at com.sun.tools.javac.code.Type$ClassType.accept(Type.java:786) at com.sun.tools.javac.code.Types$DefaultTypeVisitor.visit(Types.java:4571) at com.sun.tools.javac.code.Types.asSuper(Types.java:1952) at com.sun.tools.javac.code.Types$13.visitClassType(Types.java:1975) at com.sun.tools.javac.code.Types$13.visitClassType(Types.java:1955) at com.sun.tools.javac.code.Type$ClassType.accept(Type.java:786) at com.sun.tools.javac.code.Types$DefaultTypeVisitor.visit(Types.java:4571) at com.sun.tools.javac.code.Types.asSuper(Types.java:1952) at com.sun.tools.javac.code.Types$4.visitClassType(Types.java:921) at com.sun.tools.javac.code.Types$4.visitClassType(Types.java:844) at com.sun.tools.javac.code.Type$ClassType.accept(Type.java:786) at com.sun.tools.javac.code.Types$DefaultTypeVisitor.visit(Types.java:4571) at com.sun.tools.javac.code.Types.isSubtype(Types.java:840) at com.sun.tools.javac.code.Types.isSubtype(Types.java:804) at com.sun.tools.javac.model.JavacTypes.isSubtype(JavacTypes.java:98) at org.mapstruct.ap.internal.util.workarounds.SpecificCompilerWorkarounds.isSubtype(SpecificCompilerWorkarounds.java:76) at org.mapstruct.ap.internal.util.workarounds.TypesDecorator.isSubtype(TypesDecorator.java:68) at org.mapstruct.ap.internal.model.common.Type.isSubType(Type.java:638) at org.mapstruct.ap.internal.model.common.Type.isCollection(Type.java:628) at org.mapstruct.ap.internal.model.common.Type.isCollectionOrMap(Type.java:624) at org.mapstruct.ap.internal.model.common.Type.getAlternativeTargetAccessors(Type.java:598) at org.mapstruct.ap.internal.model.common.Type.getPropertyWriteAccessors(Type.java:419) at org.mapstruct.ap.internal.model.source.TargetReference$BuilderFromTargetMapping.getTargetEntries(TargetReference.java:144) at org.mapstruct.ap.internal.model.source.TargetReference$BuilderFromTargetMapping.build(TargetReference.java:120) at org.mapstruct.ap.internal.model.source.Mapping.init(Mapping.java:227) at org.mapstruct.ap.internal.model.source.SourceMethod$Builder.build(SourceMethod.java:207) at org.mapstruct.ap.internal.processor.MethodRetrievalProcessor.getMethodRequiringImplementation(MethodRetrievalProcessor.java:257) at org.mapstruct.ap.internal.processor.MethodRetrievalProcessor.getMethod(MethodRetrievalProcessor.java:193) at org.mapstruct.ap.internal.processor.MethodRetrievalProcessor.retrieveMethods(MethodRetrievalProcessor.java:148) at org.mapstruct.ap.internal.processor.MethodRetrievalProcessor.retrieveMethods(MethodRetrievalProcessor.java:163) at org.mapstruct.ap.internal.processor.MethodRetrievalProcessor.retrieveMethods(MethodRetrievalProcessor.java:163) at org.mapstruct.ap.internal.processor.MethodRetrievalProcessor.retrieveMethods(MethodRetrievalProcessor.java:163) at org.mapstruct.ap.internal.processor.MethodRetrievalProcessor.retrieveMethods(MethodRetrievalProcessor.java:163) at org.mapstruct.ap.internal.processor.MethodRetrievalProcessor.retrieveMethods ...

My domain classes are as follows

            @Entity
            public class User implements FirstClassDomainObject {
                @Id
                @GeneratedValue(strategy = GenerationType.IDENTITY)
                private long id;
                private String name;
                private String email;
            ...

            @Entity
            public class Exercise implements FirstClassDomainObject {
                @Id
                @GeneratedValue(strategy = GenerationType.IDENTITY)
                private long id;
                private String name;
                private String description;
            ...

            @Entity
            public class WorkoutSet implements FirstClassDomainObject {
                @Id
                @GeneratedValue(strategy = GenerationType.IDENTITY)
                private long id;
                private int repetition;
                private double wight;
                private LocalDateTime timestamp;
                @ManyToOne
                private Exercise exercise;
                @ManyToOne
                private User user;
            ...

My DTO classes are as follows

            public class UserResource implements ResourceObject {
                private Long id;
                private String name;
                private String email;
            ...

            public class ExerciseResource implements ResourceObject {
                private String name;
                private String description;
            ...

            public class WorkoutSetResource implements ResourceObject {
                private int repetition;
                private double wight;
                @JsonSerialize(using = LocalDateTimeSerializer.class)
                private LocalDateTime timestamp;
                private ExerciseResource exercise;
                private UserResource user;
            ...

My mapper interfaces are as follows

            @Mapper(componentModel = "spring")
            interface UserMapper extends ClassMapper<User, UserResource> {
                @Override
                default List<Class<?>> getSupportedClasses() {
                    return Lists.newArrayList(User.class, UserResource.class);
                }
            }


            @Mapper(componentModel = "spring")
            interface ExerciseMapper extends ClassMapper<Exercise, ExerciseResource> {
                @Override
                default List<Class<?>> getSupportedClasses() {
                    return Lists.newArrayList(Exercise.class, ExerciseResource.class);
                }
            }

            @Mapper(componentModel = "spring", uses = {UserMapper.class, WorkoutSetMapper.class})
            interface WorkoutSetMapper extends ClassMapper<WorkoutSet, WorkoutSetResource> {
                @Override
                default List<Class<?>> getSupportedClasses() {
                    return Lists.newArrayList(WorkoutSet.class, WorkoutSetResource.class);
                }
            }

The ClassMapper is defined as follows

            public interface ClassMapper<D extends DomainObject, R extends ResourceObject> {
                R map(D domainObject);
                D map(R resourceObject);
                List<Class<?>> getSupportedClasses();
            }

I've left out getter and setter methods to avoid a wall of text but the entire code base can be found here https://github.com/tonsV2/Lift-Log-Backend. Any clue about what I've done wrong?

Answer 1

I found the error! I've set the WorkoutSetMapper to use itself.

@Mapper(componentModel = "spring", uses = {UserMapper.class, WorkoutsetMapper.class})
interface WorkoutSetMapper extends ClassMapper<WorkoutSet, WorkoutSetResource> {

While I should have had

@Mapper(componentModel = "spring", uses = {UserMapper.class, ExerciseMapper.class})
interface WorkoutSetMapper extends ClassMapper<WorkoutSet, WorkoutSetResource> {