Cannot use java.util.Date

[und3rs]

My data has some fileds that type is 'java.util.Date'.
When I run my App, I faced the following error.

Invalid Cloneable interface type - interface does not expose any fields.

[application.properties]
graphql.packages=com.myproject.graphql,java.util,kotlin

I've checked the java.util.Data class and like this.
public class Date implements Serializable, Cloneable, Comparable<Date> {

Please help me.
Thank you.

[dariuszkuc]

One of the reasons we explicitly require graphql.packages property is to limit the scope of which packages can be scanned and we don't accidentally expose something we are not supposed to (like java.util.*).

See https://expediagroup.github.io/graphql-kotlin/docs/schema-generator/writing-schemas/scalars#custom-scalars. You will need to provide custom hook + logic to coerce the values (i.e. how to serialize/deserialize Date representation).

[smyrick]

graphql-java-extended-scalars also could be included.

https://github.com/graphql-java/graphql-java-extended-scalars

@dariuszkuc Do we need to modify the hooks to be able to easier include this package in the runtime?

RuntimeWiring.newRuntimeWiring().scalar(ExtendedScalars.DateTime)

[und3rs]

@dariuszkuc @smyrick
Thank you for your reply.
I tried to lots of way to solve this problem, but I can't use java.util.Date type.
Please help me. please...

I have a restful api project that completed. And I want to support graphql too.

• spring boot 2.5
• kotlin
• webflux

I've never use graphql-kotlin, so I made sample project for graphql-kotlin.

• spring boot 2.5
• kotlin
• webflux

// MockWeapon.kt
data class MockWeapon(
    val id: Long,
    val name: String,
    val date: Date
)

// MockWeaponQuery.kt
@Component
class MockWeaponQuery: Query {

    @Autowired
    private lateinit var repository: MockWeaponRepository

    fun mockWeapons(): List<MockWeapon> {
        return repository.findAll()
    }
}

// MockWeaponRepository.kt
@Component
class MockWeaponRepository {
    fun findAll(): List<MockWeapon> = listOf(MockWeapon(1, "Rod", Date()),MockWeapon(2, "Axe", Date()))
}

// build.gradle.kt
dependencies {
    implementation("org.springframework.boot", "spring-boot-starter-validation")

    implementation("org.springframework.boot:spring-boot-starter-webflux")
    implementation("com.fasterxml.jackson.module:jackson-module-kotlin")
    implementation("org.jetbrains.kotlin:kotlin-reflect")
    implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-reactor")

    implementation("com.expediagroup", "graphql-kotlin-spring-server", "4.1.1")
    implementation("com.expediagroup", "graphql-kotlin-hooks-provider", "4.1.1")
    implementation("com.expediagroup", "graphql-kotlin-schema-generator", "4.1.1")
    implementation("com.graphql-java", "graphql-java-extended-scalars", "16.0.1")
    implementation("com.zhokhov.graphql:graphql-datetime-spring-boot-starter-webflux:4.0.0")
}

//GraphqlApplication.kt
@SpringBootApplication
class GraphqlApplication

fun main(args: Array<String>) {
    runApplication<GraphqlApplication>(*args)
}

//application.properties
graphql.packages=io.myproject.zasp.graphql

That's all. If I have no 'java.util.Date', the project is working pretty well without any settings.

But when I added java.util.Date filed, I face following error.
TypeNotSupportedException: Cannot convert java.util.Date since it is not a valid GraphQL type or outside the supported packages "[io.myproject.zasp.graphql]"

Try 1.

• Adding Hooks.

// GraphqlApplication.kt
@SpringBootApplication
class GraphqlApplication

fun main(args: Array<String>) {
    val hook = object: SchemaGeneratorHooks{
        override fun willGenerateGraphQLType(type: KType): GraphQLType? {
            return when(type.classifier as? KClass<*>) {
                Date::class -> com.zhokhov.graphql.datetime.GraphQLDate()
                else -> null
            }
        }
    }

    val config = SchemaGeneratorConfig(listOf("io.myproject.zasp.graphql.data"), hooks = hook)
    val queries = listOf(TopLevelObject(MockWeaponQuery()))
    toSchema(config, queries)

    runApplication<GraphqlApplication>(*args)
}

The following error occured.

TypeNotSupportedException: Cannot convert java.util.Date since it is not a valid GraphQL type or outside the supported packages "[io.myproject.zasp.graphql]"

Try 2.

Adding "java.util" package.

// GraphqlApplication.kt
@SpringBootApplication
class GraphqlApplication

fun main(args: Array<String>) {
    val hook = object: SchemaGeneratorHooks{
        override fun willGenerateGraphQLType(type: KType): GraphQLType? {
            return when(type.classifier as? KClass<*>) {
                Date::class -> com.zhokhov.graphql.datetime.GraphQLDate()
                else -> null
            }
        }
    }

    val config = SchemaGeneratorConfig(listOf("io.myproject.zasp.graphql.data", "java.util"), hooks = hook)
    val queries = listOf(TopLevelObject(MockWeaponQuery()))
    toSchema(config, queries)

    runApplication<GraphqlApplication>(*args)
}

//application.properties
graphql.packages=io.myproject.zasp.graphql,java.util

Error:

TypeNotSupportedException: Cannot convert kotlin.Cloneable since it is not a valid GraphQL type or outside the supported packages "[io.myproject.zasp.graphql, java.util]"

Try 3.

Adding kotlin package.

// GraphqlApplication.kt
@SpringBootApplication
class GraphqlApplication

fun main(args: Array<String>) {
    val hook = object: SchemaGeneratorHooks{
        override fun willGenerateGraphQLType(type: KType): GraphQLType? {
            return when(type.classifier as? KClass<*>) {
                Date::class -> com.zhokhov.graphql.datetime.GraphQLDate()
                else -> null
            }
        }
    }

    val config = SchemaGeneratorConfig(listOf("io.myproject.zasp.graphql.data", "java.util", "kotlin"), hooks = hook)
    val queries = listOf(TopLevelObject(MockWeaponQuery()))
    toSchema(config, queries)

    runApplication<GraphqlApplication>(*args)
}

//application.properties
graphql.packages=io.myproject.zasp.graphql,java.util,kotlin

Error:

EmptyInterfaceTypeException: Invalid Cloneable interface type - interface does not expose any fields.

Try 4.

Using RuntimeWiring.

// GraphqlApplication.kt
@SpringBootApplication
class GraphqlApplication

fun main(args: Array<String>) {
    RuntimeWiring.newRuntimeWiring().scalar(ExtendedScalars.DateTime)
    RuntimeWiring.newRuntimeWiring().scalar(com.zhokhov.graphql.datetime.GraphQLDate())
    runApplication<GraphqlApplication>(*args)
}

//application.properties
graphql.packages=io.myproject.zasp.graphql

Error:

TypeNotSupportedException: Cannot convert java.util.Date since it is not a valid GraphQL type or outside the supported packages "[io.myproject.zasp.graphql]"

Try 5.

Adding 'java.util.Date' and 'kotlin' package.

// GraphqlApplication.kt
@SpringBootApplication
class GraphqlApplication

fun main(args: Array<String>) {
    RuntimeWiring.newRuntimeWiring().scalar(ExtendedScalars.DateTime)
    RuntimeWiring.newRuntimeWiring().scalar(com.zhokhov.graphql.datetime.GraphQLDate())
    runApplication<GraphqlApplication>(*args)
}

//application.properties
graphql.packages=io.myproject.zasp.graphql,java.util,kotlin

Error:

EmptyInterfaceTypeException: Invalid Cloneable interface type - interface does not expose any fields.

Try 6.

Using configuration.(DI)

@SpringBootApplication
class GraphqlApplication

fun main(args: Array<String>) {
    runApplication<GraphqlApplication>(*args)
}

graphql.packages=io.zepeto.zasp.graphql,java.util,kotlin

/ AppConfiguration.kt
@Configuration
class AppConfiguration {
    @Bean
    fun cloneable(): GraphQLScalarType {
        return com.zhokhov.graphql.datetime.GraphQLDate()
    }
}

Error:

EmptyInterfaceTypeException: Invalid Cloneable interface type - interface does not expose any fields.

Can't I use 'java.util.Date'?

PLEASE HELP ME!!
Thank you.

[und3rs]

I solved the problem with using SchemaGeneratorHooks with @bean.
Thank you.

[smyrick]

Here is the list of beans you can override: https://expediagroup.github.io/graphql-kotlin/docs/server/spring-server/spring-beans

[und3rs]

Thank you for your kindess.
I’ve had to set graphql in a hurry, so I missed that page.