Shinsuke Sugaya <******@****.***> 1756627257 +0900

# ADR-0007 - Support running Gradle on multiple Java versions and do not embed a Java runtime in the Gradle distribution

## Status

- PROPOSED on 2024-12-20

## Context

### Embedding a Java runtime in the Gradle distribution

There have been discussions on embedding a Java runtime in the Gradle distribution.
This would allow users to run Gradle without having to install a Java runtime beforehand.

# This file is used with all of the non-matrix tests in Jenkins.

# This .properties file defines the versions of Java with which to
# build and test Elasticsearch for this branch. Valid Java versions
# are 'java' or 'openjdk' followed by the major release number.

ES_BUILD_JAVA=jdk16

public final class okhttp3/java/net/cookiejar/JavaNetCookieJar : okhttp3/CookieJar {
	public fun <init> (Ljava/net/CookieHandler;)V
	public fun loadForRequest (Lokhttp3/HttpUrl;)Ljava/util/List;
	public fun saveFromResponse (Lokhttp3/HttpUrl;Ljava/util/List;)V

- **Version Compatibility:**
With Java serialization, even minor changes to a class (like adding a field) can break compatibility.

- **Cross-Language Compatibility:**
Java serialization is inherently Java-centric and does not support cross-language scenarios well.

- **Type Safety:**
Java serialization does not enforce type safety as strictly as some alternatives, potentially leading to runtime errors.

---
jjbb-template: matrix-gradle-unix.yml
vars:
  - job-name: elastic+elasticsearch+%BRANCH%+periodic+java-fips-matrix
  - job-display-name: "elastic / elasticsearch # %BRANCH% - java fips compatibility matrix"
  - job-description: "Testing of the Elasticsearch %BRANCH% branch java FIPS compatibility matrix.\n"
  - matrix-yaml-file: ".ci/matrix-runtime-javas-fips.yml"
  - matrix-variable: ES_RUNTIME_JAVA

 * @since 15.0
 */
@GwtIncompatible // java.lang.System#getProperty
public enum StandardSystemProperty {

  /** Java Runtime Environment version. */
  JAVA_VERSION("java.version"),

  /** Java Runtime Environment vendor. */
  JAVA_VENDOR("java.vendor"),

  /** Java vendor URL. */
  JAVA_VENDOR_URL("java.vendor.url"),

  /** Java installation directory. */
  JAVA_HOME("java.home"),

 * @since 15.0
 */
@GwtIncompatible // java.lang.System#getProperty
public enum StandardSystemProperty {

  /** Java Runtime Environment version. */
  JAVA_VERSION("java.version"),

  /** Java Runtime Environment vendor. */
  JAVA_VENDOR("java.vendor"),

  /** Java vendor URL. */
  JAVA_VENDOR_URL("java.vendor.url"),

  /** Java installation directory. */
  JAVA_HOME("java.home"),

/**
 * Represents a Java toolchain in the Maven build system.
 *
 * <p>A Java toolchain is a specific type of toolchain that provides access
 * to Java development tools, such as the Java compiler and Java runtime
 * environment. This interface allows users to define and configure
 * Java-related toolchains that can be utilized during the build process
 * in Maven.</p>
 *

import org.gradle.api.GradleException;

import java.util.List;
import java.util.Optional;

public class JavaUtil {

    /** A convenience method for getting java home for a version of java and requiring that version for the given task to execute */
    public static String getJavaHome(final int version) {
        List<JavaHome> javaHomes = BuildParams.getJavaVersions();