chore(build): Compile with a JDK 21 toolchain and upgrade Mockito and Error Prone

.github/workflows/agp-matrix.yml

@@ -36,7 +36,7 @@ jobs:
         uses: actions/setup-java@de7274f081f381c8f8158605e0321c36c376e2e6 # v6.0.1
         with:
           distribution: 'temurin'
-          java-version: '17'
+          java-version: '21'
 
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@3f5f9adaf7d9fecd50b5935e54106014257a94e6 # v6.4.0

.github/workflows/build.yml

@@ -11,7 +11,7 @@ concurrency:
 
 jobs:
   build:
-    name: Build Job ubuntu-latest - Java 17
+    name: Build Job ubuntu-latest
     runs-on: ubuntu-latest
 
     env:
@@ -28,7 +28,7 @@ jobs:
         uses: actions/setup-java@de7274f081f381c8f8158605e0321c36c376e2e6 # v6.0.1
         with:
           distribution: 'temurin'
-          java-version: '17'
+          java-version: '21'
 
       # Workaround for https://github.com/gradle/actions/issues/21 to use config cache
       - name: Cache buildSrc

.github/workflows/codeql-analysis.yml

@@ -28,7 +28,7 @@ jobs:
         uses: actions/setup-java@de7274f081f381c8f8158605e0321c36c376e2e6 # v6.0.1
         with:
           distribution: 'temurin'
-          java-version: '17'
+          java-version: '21'
 
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@3f5f9adaf7d9fecd50b5935e54106014257a94e6 # v6.4.0

.github/workflows/enforce-license-compliance.yml

@@ -17,7 +17,7 @@ jobs:
         uses: actions/setup-java@de7274f081f381c8f8158605e0321c36c376e2e6 # v6.0.1
         with:
           distribution: 'temurin'
-          java-version: '17'
+          java-version: '21'
 
       - name: Checkout
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1

.github/workflows/format-code.yml

@@ -16,7 +16,7 @@ jobs:
         uses: actions/setup-java@de7274f081f381c8f8158605e0321c36c376e2e6 # v6.0.1
         with:
           distribution: 'temurin'
-          java-version: '17'
+          java-version: '21'
 
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@3f5f9adaf7d9fecd50b5935e54106014257a94e6 # v6.4.0

.github/workflows/generate-javadocs.yml

@@ -17,7 +17,7 @@ jobs:
         uses: actions/setup-java@de7274f081f381c8f8158605e0321c36c376e2e6 # v6.0.1
         with:
           distribution: 'temurin'
-          java-version: '17'
+          java-version: '21'
 
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@3f5f9adaf7d9fecd50b5935e54106014257a94e6 # v6.4.0

.github/workflows/integration-tests-macrobenchmark.yml

@@ -26,7 +26,7 @@ jobs:
         uses: actions/setup-java@de7274f081f381c8f8158605e0321c36c376e2e6 # v6.0.1
         with:
           distribution: 'temurin'
-          java-version: '17'
+          java-version: '21'
 
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@3f5f9adaf7d9fecd50b5935e54106014257a94e6 # v6.4.0

.github/workflows/integration-tests-size.yml

@@ -26,7 +26,7 @@ jobs:
         uses: actions/setup-java@de7274f081f381c8f8158605e0321c36c376e2e6 # v6.0.1
         with:
           distribution: "temurin"
-          java-version: "17"
+          java-version: "21"
 
       # Workaround for https://github.com/gradle/actions/issues/21 to use config cache
       - name: Cache buildSrc

.github/workflows/integration-tests-ui-critical.yml

@@ -33,7 +33,7 @@ jobs:
         uses: actions/setup-java@de7274f081f381c8f8158605e0321c36c376e2e6 # v6.0.1
         with:
           distribution: 'temurin'
-          java-version: '17'
+          java-version: '21'
 
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@3f5f9adaf7d9fecd50b5935e54106014257a94e6 # v6.4.0

.github/workflows/integration-tests-ui.yml

@@ -30,7 +30,7 @@ jobs:
         uses: actions/setup-java@de7274f081f381c8f8158605e0321c36c376e2e6 # v6.0.1
         with:
           distribution: 'temurin'
-          java-version: '17'
+          java-version: '21'
 
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@3f5f9adaf7d9fecd50b5935e54106014257a94e6 # v6.4.0

.github/workflows/release-build.yml

@@ -23,7 +23,7 @@ jobs:
         uses: actions/setup-java@de7274f081f381c8f8158605e0321c36c376e2e6 # v6.0.1
         with:
           distribution: 'temurin'
-          java-version: '17'
+          java-version: '21'
 
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@3f5f9adaf7d9fecd50b5935e54106014257a94e6 # v6.4.0

.github/workflows/spring-boot-2-matrix.yml

@@ -48,7 +48,7 @@ jobs:
         uses: actions/setup-java@de7274f081f381c8f8158605e0321c36c376e2e6 # v6.0.1
         with:
           distribution: 'temurin'
-          java-version: '17'
+          java-version: '21'
 
       # Workaround for https://github.com/gradle/actions/issues/21 to use config cache
       - name: Cache buildSrc

.github/workflows/spring-boot-3-matrix.yml

@@ -48,7 +48,7 @@ jobs:
         uses: actions/setup-java@de7274f081f381c8f8158605e0321c36c376e2e6 # v6.0.1
         with:
           distribution: 'temurin'
-          java-version: '17'
+          java-version: '21'
 
       # Workaround for https://github.com/gradle/actions/issues/21 to use config cache
       - name: Cache buildSrc

.github/workflows/spring-boot-4-matrix.yml

@@ -48,7 +48,7 @@ jobs:
         uses: actions/setup-java@de7274f081f381c8f8158605e0321c36c376e2e6 # v6.0.1
         with:
           distribution: 'temurin'
-          java-version: '17'
+          java-version: '21'
 
       # Workaround for https://github.com/gradle/actions/issues/21 to use config cache
       - name: Cache buildSrc

.github/workflows/system-tests-backend.yml

@@ -121,7 +121,7 @@ jobs:
         uses: actions/setup-java@de7274f081f381c8f8158605e0321c36c376e2e6 # v6.0.1
         with:
           distribution: 'temurin'
-          java-version: '17'
+          java-version: '21'
 
       - name: Setup Gradle
         uses: gradle/actions/setup-gradle@3f5f9adaf7d9fecd50b5935e54106014257a94e6 # v6.4.0

CONTRIBUTING.md

@@ -5,7 +5,9 @@ We suggest opening an issue to discuss bigger changes before investing on a big
 
 # Requirements
 
-The project requires you to run JDK 17.
+The project requires you to run JDK 21 or newer. Compilation and tests always happen on JDK 21
+through a [toolchain](https://docs.gradle.org/current/userguide/toolchains.html), so a newer JDK
+runs the build but never changes its output.
 
 ## Android
 

build-logic/build.gradle.kts

@@ -9,6 +9,8 @@ repositories {
 dependencies {
   implementation(libs.animalsniffer.gradle.plugin)
   implementation(libs.spotlessLib)
+  // Only for the Kotlin task types the jvm-targets plugin configures.
+  compileOnly(libs.kotlin.gradle.plugin)
 }
 
 gradlePlugin {

build-logic/src/main/kotlin/io.sentry.jvm-targets.gradle.kts

@@ -0,0 +1,38 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+import org.jetbrains.kotlin.gradle.tasks.KotlinJvmCompile
+
+// Compilation and tests run on this JDK whatever JDK runs Gradle, so a contributor on a newer JDK
+// gets the same output as CI. Error Prone 2.50 ships Java 21 bytecode and needs javac 21 as well.
+// This picks the JDK only - every module pins the bytecode level it publishes itself.
+val buildJdk = JavaLanguageVersion.of(21)
+
+plugins.withType<JavaBasePlugin> {
+  extensions.configure<JavaPluginExtension> { toolchain { languageVersion.set(buildJdk) } }
+}
+
+/**
+ * Targets [buildJdk] in the compile tasks that [taskFilter] selects. Both languages move together,
+ * because the Kotlin plugin rejects a Java/Kotlin target mismatch.
+ */
+fun Project.applyToolchainToCompileTasks(taskFilter: (Task) -> Boolean) {
+  // AGP assigns these task properties while it creates the variants, so this has to run later.
+  afterEvaluate {
+    tasks.withType<JavaCompile>().matching(taskFilter).configureEach {
+      sourceCompatibility = buildJdk.toString()
+      targetCompatibility = buildJdk.toString()
+    }
+    tasks.withType<KotlinJvmCompile>().matching(taskFilter).configureEach {
+      compilerOptions.jvmTarget.set(JvmTarget.fromTarget(buildJdk.toString()))
+    }
+  }
+}
+
+listOf("com.android.library", "com.android.application").forEach { pluginId ->
+  plugins.withId(pluginId) {
+    // Mockito 5 and mockito-kotlin 6 are built for Java 11, so test code (never published) can't
+    // share the Java 8 target of the published code. Other modules pin main compilation only, which
+    // leaves their test tasks on the toolchain; AGP has no such split, as compileOptions applies to
+    // every variant, so its unit tests need this.
+    applyToolchainToCompileTasks { it.name.contains("UnitTest") }
+  }
+}

build.gradle.kts

@@ -29,6 +29,10 @@ plugins {
     alias(libs.plugins.sentry) apply false
 }
 
+check(JavaVersion.current().isCompatibleWith(JavaVersion.VERSION_21)) {
+    "This build requires JDK 21 or newer, but runs on JDK ${JavaVersion.current()}."
+}
+
 buildscript {
     repositories {
         google()
@@ -111,6 +115,7 @@ allprojects {
 
 subprojects {
     apply { plugin("io.sentry.spotless") }
+    apply { plugin("io.sentry.jvm-targets") }
 
     plugins.withId(Config.QualityPlugins.detektPlugin) {
         configure<DetektExtension> {
@@ -162,9 +167,14 @@ subprojects {
 
             configure<JavaPluginExtension> {
                 withJavadocJar()
+            }
 
-                sourceCompatibility = JavaVersion.VERSION_1_8
-                targetCompatibility = JavaVersion.VERSION_1_8
+            // Published code targets Java 8. release compiles against that version's class library
+            // instead of the build JDK's, so newer JDK APIs (e.g. List.getFirst()) can't leak into
+            // published bytecode. Modules that publish a higher level override this; test code is
+            // never published and follows the toolchain.
+            tasks.named<JavaCompile>("compileJava") {
+                options.release.set(8)
             }
         }
 

buildSrc/build.gradle.kts

@@ -1,13 +1,7 @@
-import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
-
 plugins {
     `kotlin-dsl`
 }
 
 repositories {
     mavenCentral()
 }
-
-tasks.withType<KotlinCompile>().configureEach {
-    compilerOptions.jvmTarget = org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_17
-}

gradle/libs.versions.toml

@@ -64,7 +64,7 @@ buildconfig = { id = "com.github.gmazzo.buildconfig", version = "5.6.5" }
 dokka = { id = "org.jetbrains.dokka", version = "2.0.0" }
 dokka-javadoc = { id = "org.jetbrains.dokka-javadoc", version = "2.0.0" }
 binary-compatibility-validator = { id = "org.jetbrains.kotlinx.binary-compatibility-validator", version = "0.13.0" }
-errorprone = { id = "net.ltgt.errorprone", version = "3.0.1" }
+errorprone = { id = "net.ltgt.errorprone", version = "5.1.1" }
 gradle-versions = { id = "com.github.ben-manes.versions", version = "0.42.0" }
 spotless = { id = "com.diffplug.spotless", version.ref = "spotless" }
 detekt = { id = "io.gitlab.arturbosch.detekt", version = "1.23.8" }
@@ -129,7 +129,7 @@ caffeine-jcache = { module = "com.github.ben-manes.caffeine:jcache", version = "
 coil-compose = { module = "io.coil-kt:coil-compose", version = "2.6.0" }
 commons-compress = {module = "org.apache.commons:commons-compress", version = "1.28.0"}
 context-propagation = { module = "io.micrometer:context-propagation", version = "1.1.0" }
-errorprone-core = { module = "com.google.errorprone:error_prone_core", version = "2.11.0" }
+errorprone-core = { module = "com.google.errorprone:error_prone_core", version = "2.50.0" }
 feign-core = { module = "io.github.openfeign:feign-core", version.ref = "feign" }
 feign-gson = { module = "io.github.openfeign:feign-gson", version.ref = "feign" }
 graphql-java17 = { module = "com.graphql-java:graphql-java", version = "17.3" }
@@ -152,9 +152,10 @@ log4j-core = { module = "org.apache.logging.log4j:log4j-core", version.ref = "lo
 leakcanary = { module = "com.squareup.leakcanary:leakcanary-android", version = "2.14" }
 lottie-compose = { module = "com.airbnb.android:lottie-compose", version = "6.7.1" }
 logback-classic = { module = "ch.qos.logback:logback-classic", version.ref = "logback" }
+kotlin-gradle-plugin = { module = "org.jetbrains.kotlin:kotlin-gradle-plugin", version.ref = "kotlin" }
 nopen-annotations = { module = "com.jakewharton.nopen:nopen-annotations", version.ref = "nopen" }
 nopen-checker = { module = "com.jakewharton.nopen:nopen-checker", version.ref = "nopen" }
-nullaway = { module = "com.uber.nullaway:nullaway", version = "0.9.5" }
+nullaway = { module = "com.uber.nullaway:nullaway", version = "0.14.2" }
 okhttp = { module = "com.squareup.okhttp3:okhttp", version.ref = "okhttp" }
 okhttp-bom = { module = "com.squareup.okhttp3:okhttp-bom", version.ref = "okhttp" }
 openfeature = { module = "dev.openfeature:sdk", version.ref = "openfeature" }
@@ -273,9 +274,8 @@ hsqldb = { module = "org.hsqldb:hsqldb", version = "2.6.1" }
 javafaker = { module = "com.github.javafaker:javafaker", version = "1.0.2" }
 kotlinx-coroutines-test = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-test", version.ref = "coroutines" }
 leakcanary-instrumentation = { module = "com.squareup.leakcanary:leakcanary-android-instrumentation", version = "2.14" }
-mockito-kotlin = { module = "org.mockito.kotlin:mockito-kotlin", version = "4.1.0" }
-mockito-kotlin-spring7 = { module = "org.mockito.kotlin:mockito-kotlin", version = "6.0.0" }
-mockito-inline = { module = "org.mockito:mockito-inline", version = "4.8.0" }
+mockito-kotlin = { module = "org.mockito.kotlin:mockito-kotlin", version = "6.4.0" }
+mockito-core = { module = "org.mockito:mockito-core", version = "5.24.0" }
 msgpack = { module = "org.msgpack:msgpack-core", version = "0.9.8" }
 okhttp-mockwebserver = { module = "com.squareup.okhttp3:mockwebserver", version.ref = "okhttp" }
 # apollo-runtime 5.x pulls in okhttp 5.x; mockwebserver 4.x is incompatible with that classpath

sentry-android-core/build.gradle.kts

@@ -118,7 +118,7 @@ dependencies {
   testImplementation(libs.awaitility.kotlin)
   testImplementation(libs.google.truth)
   testImplementation(libs.mockito.kotlin)
-  testImplementation(libs.mockito.inline)
+  testImplementation(libs.mockito.core)
   testImplementation(projects.sentryTestSupport)
   testImplementation(projects.sentrySpotlight)
   testImplementation(projects.sentryAndroidFragment)

sentry-android-core/src/main/java/io/sentry/android/core/ApplicationNotResponding.java

@@ -14,12 +14,14 @@
  * really the cause of the exception. Each "Caused by" is the stack trace of a running thread. Note
  * that the main thread always comes first.
  */
 final class ApplicationNotResponding extends RuntimeException {
   private static final long serialVersionUID = 252541144579117016L;
 
+  // Never serialized.
+  @SuppressWarnings("serial")
   private final @Nullable Thread thread;
 
   ApplicationNotResponding(final @Nullable String message) {
     super(message);
     this.thread = null;
   }

sentry-android-core/src/main/java/io/sentry/android/core/SentryUserFeedbackButton.java

@@ -13,6 +13,8 @@
 /**
  * @deprecated `SentryUserFeedbackButton` will be removed in the next major version
  */
+// Constructors call overridable methods; making them final would break the public API.
+@SuppressWarnings("this-escape")
 @Deprecated
 public class SentryUserFeedbackButton extends Button {
 

sentry-android-core/src/main/java/io/sentry/android/core/performance/AppStartMetrics.java

@@ -50,6 +50,8 @@
  * <p>This class is also responsible for - determining the app start type (cold, warm) - determining
  * if the app was launched in foreground
  */
+// Constructors call overridable methods; making them final would break the public API.
+@SuppressWarnings("this-escape")
 @ApiStatus.Internal
 public class AppStartMetrics extends ActivityLifecycleCallbacksAdapter {
   public interface HeadlessAppStartListener {

sentry-android-core/src/test/java/io/sentry/android/core/ApplicationExitIntegrationTestBase.kt

@@ -27,6 +27,7 @@ import org.junit.Rule
 import org.junit.rules.TemporaryFolder
 import org.mockito.kotlin.any
 import org.mockito.kotlin.anyOrNull
+import org.mockito.kotlin.anyVararg
 import org.mockito.kotlin.argThat
 import org.mockito.kotlin.atMost
 import org.mockito.kotlin.check
@@ -316,7 +317,7 @@ abstract class ApplicationExitIntegrationTestBase<THint : Any> {
       .log(
         any(),
         argThat { startsWith("Timed out waiting to flush previous session to its own file.") },
-        any<Any>(),
+        anyVararg<Any>(),
       )
   }
 
@@ -337,7 +338,7 @@ abstract class ApplicationExitIntegrationTestBase<THint : Any> {
       .log(
         any(),
         argThat { startsWith("Timed out waiting to flush previous session to its own file.") },
-        any<Any>(),
+        anyVararg<Any>(),
       )
     verify(fixture.scopes).captureEvent(any(), any<Hint>())
   }
@@ -354,7 +355,7 @@ abstract class ApplicationExitIntegrationTestBase<THint : Any> {
       .log(
         any(),
         argThat { startsWith("Timed out waiting to flush previous session to its own file.") },
-        any<Any>(),
+        anyVararg<Any>(),
       )
     assertTrue((fixture.options.envelopeDiskCache as EnvelopeCache).waitPreviousSessionFlush())
   }

sentry-android-fragment/build.gradle.kts

@@ -70,7 +70,7 @@ dependencies {
   testImplementation(libs.androidx.fragment.ktx)
   testImplementation(libs.kotlin.test.junit)
   testImplementation(libs.mockito.kotlin)
-  testImplementation(libs.mockito.inline)
+  testImplementation(libs.mockito.core)
 }
 
 tasks.withType<Detekt>().configureEach {

sentry-android-integration-tests/sentry-uitest-android-critical/build.gradle.kts

@@ -1,5 +1,4 @@
 import io.gitlab.arturbosch.detekt.Detekt
-import org.jetbrains.kotlin.gradle.dsl.JvmTarget
 
 plugins {
   id("com.android.application")
@@ -33,7 +32,6 @@ android {
       proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro")
     }
   }
-  kotlin { compilerOptions.jvmTarget = JvmTarget.JVM_11 }
   buildFeatures { compose = true }
   composeOptions { kotlinCompilerExtensionVersion = libs.versions.composeCompiler.get() }
   androidComponents.beforeVariants {