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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"SimplePerformantInstrumentation hooks declares InstrumentationState non-null but createState returns null by default","articleBody":"**Describe the bug**\nIn graphql-java 26, `SimplePerformantInstrumentation` is annotated with `@NullMarked`. Its unannotated `InstrumentationState` callback parameters are therefore exposed to Kotlin as non-null.\n\nHowever, `createState()` and `createStateAsync()` remain explicitly nullable, and the default `SimplePerformantInstrumentation.createState()` implementation returns `null`.\n\nThis appears to be a nullability-contract mismatch introduced by the [JSpecify instrumentation changes in #4272](https://github.com/graphql-java/graphql-java/pull/4272).\n\nThe callback state parameters should either be annotated `@Nullable`, matching the existing optional-state behavior, or graphql-java should guarantee a non-null empty state. Making the parameters nullable would preserve the existing runtime contract.\n\n**To Reproduce**\nPlease provide a code example or even better a test to reproduce the bug.\n\n```kotlin\n  import graphql.ExecutionResult\n  import graphql.GraphQL\n  import graphql.execution.instrumentation.InstrumentationContext\n  import graphql.execution.instrumentation.InstrumentationState\n  import graphql.execution.instrumentation.SimplePerformantInstrumentation\n  import graphql.execution.instrumentation.parameters.InstrumentationExecutionParameters\n  import graphql.schema.idl.RuntimeWiring\n  import graphql.schema.idl.SchemaGenerator\n  import graphql.schema.idl.SchemaParser\n  import kotlin.test.Test\n\n  class InstrumentationStateNullabilityTest {\n\n      private class StatelessInstrumentation : SimplePerformantInstrumentation() {\n          override fun beginExecution(\n              parameters: InstrumentationExecutionParameters,\n              state: InstrumentationState\n          ): InstrumentationContext\u003cExecutionResult>? = null\n      }\n\n      @Test\n      fun `stateless Kotlin instrumentation should execute without an NPE`() {\n          val typeRegistry = SchemaParser().parse(\n              \"\"\"\n              type Query {\n                  hello: String\n              }\n              \"\"\".trimIndent()\n          )\n          val schema = SchemaGenerator().makeExecutableSchema(\n              typeRegistry,\n              RuntimeWiring.MOCKED_WIRING\n          )\n          val graphQL = GraphQL.newGraphQL(schema)\n              .instrumentation(StatelessInstrumentation())\n              .build()\n\n          graphQL.execute(\"{ hello }\")\n      }\n  }\n```\n\nThe execution fails when `beginExecution` is invoked:\n\n```\n  java.lang.NullPointerException:\n  Parameter specified as non-null is null:\n  method StatelessInstrumentation.beginExecution, parameter state\n```\n\nA current workaround is to return a non-null marker state:\n\n```kotlin\nprivate object EmptyInstrumentationState : InstrumentationState\n\n override fun createState(\n      parameters: InstrumentationCreateStateParameters\n  ): InstrumentationState = EmptyInstrumentationState\n```\n","author":{"url":"https://github.com/samuelAndalon","@type":"Person","name":"samuelAndalon"},"datePublished":"2026-08-04T22:19:29Z","url":"https://github.com/graphql-java/graphql-java/issues/4433"}