Deprecate versions of Java prior to Java 11 (#40756)

This commit deprecates versions of Java prior to Java 11. This commit
will cause a warning to be printed to standard error when any command
line tool is invoked, or when Elasticsearch is started. Additionally, we
log a deprecation message when Elasticsearch is started.

distribution/tools/java-version-checker/src/main/java/org/elasticsearch/tools/java_version_checker/JavaVersion.java

@@ -27,6 +27,7 @@ public class JavaVersion {
 
     public static final List<Integer> CURRENT = parse(System.getProperty("java.specification.version"));
     public static final List<Integer> JAVA_8 = parse("1.8");
+    public static final List<Integer> JAVA_11 = parse("11");
 
     static List<Integer> parse(final String value) {
         if (!value.matches("^0*[0-9]+(\\.[0-9]+)*$")) {
@@ -66,5 +67,4 @@ public class JavaVersion {
         return 0;
     }
 
-
 }

distribution/tools/java-version-checker/src/main/java/org/elasticsearch/tools/java_version_checker/JavaVersionChecker.java

@@ -48,6 +48,13 @@ final class JavaVersionChecker {
             errPrintln(message);
             exit(1);
         }
+        if (JavaVersion.compare(JavaVersion.CURRENT, JavaVersion.JAVA_11) < 0) {
+            final String message = String.format(
+                    Locale.ROOT,
+                    "future versions of Elasticsearch will require Java 11; your Java version from [%s] does not meet this requirement",
+                    System.getProperty("java.home"));
+            errPrintln(message);
+        }
         exit(0);
     }
 

qa/vagrant/src/test/resources/packaging/tests/60_systemd.bats

@@ -106,7 +106,7 @@ setup() {
 
     # Verifies that no new entries in journald have been added
     # since the last start
-    result="$(journalctl _SYSTEMD_UNIT=elasticsearch.service --since "$since" --output cat | wc -l)"
+    result="$(journalctl _SYSTEMD_UNIT=elasticsearch.service --since "$since" --output cat | grep -v "future versions of Elasticsearch will require Java 11" | wc -l)"
     [ "$result" -eq "0" ] || {
             echo "Expected no entries in journalctl for the Elasticsearch service but found:"
             journalctl _SYSTEMD_UNIT=elasticsearch.service --since "$since"

server/src/main/java/org/elasticsearch/bootstrap/Bootstrap.java

@@ -19,14 +19,13 @@
 
 package org.elasticsearch.bootstrap;
 
-import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.core.Appender;
 import org.apache.logging.log4j.core.LoggerContext;
 import org.apache.logging.log4j.core.appender.ConsoleAppender;
 import org.apache.logging.log4j.core.config.Configurator;
 import org.apache.lucene.util.Constants;
-import org.elasticsearch.core.internal.io.IOUtils;
 import org.apache.lucene.util.StringHelper;
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.Version;
@@ -34,6 +33,7 @@ import org.elasticsearch.cli.UserException;
 import org.elasticsearch.common.PidFile;
 import org.elasticsearch.common.SuppressForbidden;
 import org.elasticsearch.common.inject.CreationException;
+import org.elasticsearch.common.logging.DeprecationLogger;
 import org.elasticsearch.common.logging.LogConfigurator;
 import org.elasticsearch.common.logging.Loggers;
 import org.elasticsearch.common.network.IfConfig;
@@ -41,6 +41,7 @@ import org.elasticsearch.common.settings.KeyStoreWrapper;
 import org.elasticsearch.common.settings.SecureSettings;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.transport.BoundTransportAddress;
+import org.elasticsearch.core.internal.io.IOUtils;
 import org.elasticsearch.env.Environment;
 import org.elasticsearch.monitor.jvm.JvmInfo;
 import org.elasticsearch.monitor.os.OsProbe;
@@ -58,6 +59,7 @@ import java.nio.file.Path;
 import java.security.NoSuchAlgorithmException;
 import java.util.Collections;
 import java.util.List;
+import java.util.Locale;
 import java.util.concurrent.CountDownLatch;
 
 /**
@@ -295,6 +297,14 @@ final class Bootstrap {
         } catch (IOException e) {
             throw new BootstrapException(e);
         }
+        if (JavaVersion.current().compareTo(JavaVersion.parse("11")) < 0) {
+            final String message = String.format(
+                            Locale.ROOT,
+                            "future versions of Elasticsearch will require Java 11; " +
+                                    "your Java version from [%s] does not meet this requirement",
+                            System.getProperty("java.home"));
+            new DeprecationLogger(LogManager.getLogger(Bootstrap.class)).deprecated(message);
+        }
         if (environment.pidFile() != null) {
             try {
                 PidFile.create(environment.pidFile(), true);