set language version explicitly (#915)

Co-authored-by: Trask Stalnaker <trask.stalnaker@gmail.com>

Author: zeitlinger

doc-snippets/extensions-minimal/build.gradle.kts

@@ -3,6 +3,12 @@ plugins {
     id("com.gradleup.shadow")
 }
 
+java {
+    toolchain {
+        languageVersion.set(JavaLanguageVersion.of(8))
+    }
+}
+
 dependencies {
     // Use BOM to manage OpenTelemetry dependency versions
     compileOnly(platform("io.opentelemetry:opentelemetry-bom:1.56.0"))
@@ -23,4 +29,4 @@ dependencies {
 
 tasks.assemble {
     dependsOn(tasks.shadowJar)
-}
+}

doc-snippets/extensions-testapp/build.gradle.kts

@@ -6,6 +6,12 @@ plugins {
 group = "org.example"
 version = "1.0-SNAPSHOT"
 
+java {
+    toolchain {
+        languageVersion.set(JavaLanguageVersion.of(8))
+    }
+}
+
 repositories {
     mavenCentral()
 }
@@ -20,4 +26,4 @@ tasks.jar {
     }
     duplicatesStrategy = DuplicatesStrategy.EXCLUDE
     from(configurations.runtimeClasspath.get().map { if (it.isDirectory) it else zipTree(it) })
-}
+}

javaagent-declarative-configuration/build.gradle.kts

@@ -6,6 +6,13 @@ plugins {
     id("org.springframework.boot") version "3.5.8"
 }
 
+java {
+    toolchain {
+        // due to Spring Boot 3 requirement, not because of declarative config support
+        languageVersion.set(JavaLanguageVersion.of(17))
+    }
+}
+
 description = "OpenTelemetry Java Agent Declarative Configuration Example"
 val moduleName by extra { "io.opentelemetry.examples.javaagent.declarative" }