Modernize and consolidate JDKs usage across all stages of the build. Update JDK-14 requirement, switch to JDK-17 instead

DEVELOPER_GUIDE.md

@@ -49,7 +49,7 @@ Fork [opensearch-project/OpenSearch](https://github.com/opensearch-project/OpenS
 
 OpenSearch builds using Java 11 at a minimum. This means you must have a JDK 11 installed with the environment variable `JAVA_HOME` referencing the path to Java home for your JDK 11 installation, e.g. `JAVA_HOME=/usr/lib/jvm/jdk-11`.
 
-By default, tests use the same runtime as `JAVA_HOME`. However, since OpenSearch also supports JDK 8 as the runtime, the build supports compiling with JDK 11 and testing on a different version of JDK runtime. To do this, set `RUNTIME_JAVA_HOME` pointing to the Java home of another JDK installation, e.g. `RUNTIME_JAVA_HOME=/usr/lib/jvm/jdk-8`.
+By default, the test tasks use bundled JDK runtime, configured in `buildSrc/version.properties` and set to JDK 17 (LTS). Other kind of test tasks (integration, cluster, ... ) use the same runtime as `JAVA_HOME`. However, since OpenSearch supports JDK 8 as the runtime, the build supports compiling with JDK 11 and testing on a different version of JDK runtime. To do this, set `RUNTIME_JAVA_HOME` pointing to the Java home of another JDK installation, e.g. `RUNTIME_JAVA_HOME=/usr/lib/jvm/jdk-8`. Alernatively, the runtime JDK version could be provided as the command line argument, using combination of `runtime.java=<major JDK version>` property and `JAVA<major JDK version>_HOME` environment variable, for exampe `./gradlew -Druntime.java=17 ...` (in this case, the tooling expects `JAVA17_HOME` environment variable to be set).
 
 To run the full suite of tests you will also need `JAVA8_HOME`, `JAVA11_HOME`, and `JAVA14_HOME`. They are required by the [backwards compatibility test](./TESTING.md#testing-backwards-compatibility).
 
@@ -70,8 +70,8 @@ Start by running the test suite with `gradlew check`. This should complete witho
 OpenSearch Build Hamster says Hello!
   Gradle Version        : 6.6.1
   OS Info               : Linux 5.4.0-1037-aws (amd64)
-  JDK Version           : 14 (JDK)
-  JAVA_HOME             : /usr/lib/jvm/java-14-openjdk-amd64
+  JDK Version           : 11 (JDK)
+  JAVA_HOME             : /usr/lib/jvm/java-11-openjdk-amd64
 =======================================
 
 ...
@@ -133,7 +133,7 @@ Use `-Dtests.opensearch.` to pass additional settings to the running instance. F
 
 ### IntelliJ IDEA
 
-When importing into IntelliJ you will need to define an appropriate JDK. The convention is that **this SDK should be named "14"**, and the project import will detect it automatically. For more details on defining an SDK in IntelliJ please refer to [this documentation](https://www.jetbrains.com/help/idea/sdk.html#define-sdk). Note that SDK definitions are global, so you can add the JDK from any project, or after project import. Importing with a missing JDK will still work, IntelliJ will report a problem and will refuse to build until resolved.
+When importing into IntelliJ you will need to define an appropriate JDK. The convention is that **this SDK should be named "11"**, and the project import will detect it automatically. For more details on defining an SDK in IntelliJ please refer to [this documentation](https://www.jetbrains.com/help/idea/sdk.html#define-sdk). Note that SDK definitions are global, so you can add the JDK from any project, or after project import. Importing with a missing JDK will still work, IntelliJ will report a problem and will refuse to build until resolved.
 
 You can import the OpenSearch project into IntelliJ IDEA as follows.
 

buildSrc/src/integTest/resources/org/opensearch/gradle/internal/fake_git/remote/.ci/java-versions.properties

@@ -27,6 +27,6 @@
 # specific language governing permissions and limitations
 # under the License.
 #
-OPENSEARCH_BUILD_JAVA=openjdk14
-OPENSEARCH_RUNTIME_JAVA=openjdk14
+OPENSEARCH_BUILD_JAVA=openjdk11
+OPENSEARCH_RUNTIME_JAVA=java8
 GRADLE_TASK=build

buildSrc/src/main/java/org/opensearch/gradle/info/GlobalBuildInfoPlugin.java

@@ -65,6 +65,7 @@
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Random;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -75,7 +76,6 @@ public class GlobalBuildInfoPlugin implements Plugin<Project> {
     private static final String DEFAULT_LEGACY_VERSION_JAVA_FILE_PATH = "server/src/main/java/org/opensearch/LegacyESVersion.java";
     private static final String DEFAULT_VERSION_JAVA_FILE_PATH = "server/src/main/java/org/opensearch/Version.java";
     private static Integer _defaultParallel = null;
-    private static Boolean _isBundledJdkSupported = null;
 
     private final JavaInstallationRegistry javaInstallationRegistry;
     private final ObjectFactory objects;
@@ -101,7 +101,8 @@ public void apply(Project project) {
         JavaVersion minimumCompilerVersion = JavaVersion.toVersion(Util.getResourceContents("/minimumCompilerVersion"));
         JavaVersion minimumRuntimeVersion = JavaVersion.toVersion(Util.getResourceContents("/minimumRuntimeVersion"));
 
-        File runtimeJavaHome = findRuntimeJavaHome();
+        Optional<File> runtimeJavaHomeOpt = findRuntimeJavaHome();
+        File runtimeJavaHome = runtimeJavaHomeOpt.orElse(Jvm.current().getJavaHome());
 
         File rootDir = project.getRootDir();
         GitInfo gitInfo = gitInfo(rootDir);
@@ -113,7 +114,7 @@ public void apply(Project project) {
             params.reset();
             params.setRuntimeJavaHome(runtimeJavaHome);
             params.setRuntimeJavaVersion(determineJavaVersion("runtime java.home", runtimeJavaHome, minimumRuntimeVersion));
-            params.setIsRutimeJavaHomeSet(Jvm.current().getJavaHome().equals(runtimeJavaHome) == false);
+            params.setIsRutimeJavaHomeSet(runtimeJavaHomeOpt.isPresent());
             params.setRuntimeJavaDetails(getJavaInstallation(runtimeJavaHome).getImplementationName());
             params.setJavaVersions(getAvailableJavaVersions(minimumCompilerVersion));
             params.setMinimumCompilerVersion(minimumCompilerVersion);
@@ -262,14 +263,14 @@ private static void throwInvalidJavaHomeException(String description, File javaH
         throw new GradleException(message);
     }
 
-    private static File findRuntimeJavaHome() {
+    private static Optional<File> findRuntimeJavaHome() {
         String runtimeJavaProperty = System.getProperty("runtime.java");
 
         if (runtimeJavaProperty != null) {
-            return new File(findJavaHome(runtimeJavaProperty));
+            return Optional.of(new File(findJavaHome(runtimeJavaProperty)));
         }
 
-        return System.getenv("RUNTIME_JAVA_HOME") == null ? Jvm.current().getJavaHome() : new File(System.getenv("RUNTIME_JAVA_HOME"));
+        return System.getenv("RUNTIME_JAVA_HOME") == null ? Optional.empty() : Optional.of(new File(System.getenv("RUNTIME_JAVA_HOME")));
     }
 
     private static String findJavaHome(String version) {

buildSrc/src/main/java/org/opensearch/gradle/test/DistroTestPlugin.java

@@ -76,8 +76,8 @@
 public class DistroTestPlugin implements Plugin<Project> {
     private static final String SYSTEM_JDK_VERSION = "8u242+b08";
     private static final String SYSTEM_JDK_VENDOR = "adoptopenjdk";
-    private static final String GRADLE_JDK_VERSION = "14+36@076bab302c7b4508975440c56f6cc26a";
-    private static final String GRADLE_JDK_VENDOR = "openjdk";
+    private static final String GRADLE_JDK_VERSION = "17+35";
+    private static final String GRADLE_JDK_VENDOR = "adoptium";
 
     // all distributions used by distro tests. this is temporary until tests are per distribution
     private static final String EXAMPLE_PLUGIN_CONFIGURATION = "examplePlugin";