build: Pin the Gradle daemon to JDK 21 (#6364)

* build: Pin the Gradle daemon to JDK 21

Since #6242 the build needs JDK 21 to run Gradle. Daemon JVM criteria
let Gradle pick an installed JDK 21 regardless of JAVA_HOME.

Also write a heap dump on daemon OOM instead of crashing, and silence
Gradle's welcome message and Android Studio's AGP upgrade prompt.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

* build: Drop the JDK 21 check now that the daemon JVM is pinned

The daemon JVM criteria only accept JDK 21, so the check can't fail.
CONTRIBUTING.md no longer claims a newer JDK runs the build.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Author: runningcode

CONTRIBUTING.md

@@ -36,9 +36,10 @@ You are welcome to use whatever tools you prefer for making a contribution. Howe
 
 # Requirements
 
-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.
+The project requires JDK 21. Gradle finds it through
+[toolchain auto-detection](https://docs.gradle.org/current/userguide/toolchains.html#sec:auto_detection)
+(SDKMAN!, asdf, IntelliJ, ...) and uses it for the build, compilation and tests, whatever JDK
+`JAVA_HOME` points to.
 
 ## Android
 

build.gradle.kts

@@ -29,10 +29,6 @@ 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()

gradle.properties

@@ -1,10 +1,11 @@
 # Daemons heap size
-org.gradle.jvmargs=-Xmx8g -XX:MaxMetaspaceSize=2g -XX:+CrashOnOutOfMemoryError -Dfile.encoding=UTF-8 -XX:+UseParallelGC
+org.gradle.jvmargs=-Xmx8g -XX:MaxMetaspaceSize=2g -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8 -XX:+UseParallelGC
 org.gradle.caching=true
 org.gradle.parallel=true
 org.gradle.configureondemand=true
 org.gradle.configuration-cache=true
 org.gradle.configuration-cache.parallel=true
+org.gradle.welcome=never
 
 org.jetbrains.dokka.experimental.gradle.pluginMode=V2Enabled
 
@@ -15,6 +16,8 @@ android.builtInKotlin=false
 android.newDsl=false
 android.experimental.lint.version=9.4.0
 
+android.disableAgpUpgradePrompt=true
+
 # Release information
 versionName=8.61.1
 

gradle/gradle-daemon-jvm.properties

@@ -0,0 +1 @@
+toolchainVersion=21