Add JavaVersionChecker to check Java version for compatibility before… (

#13356)

* Add JavaVersionChecker to check Java version for compatibility before running

Provides a "friendly" error message when running Logstash with an incompatible
version of Java

* Add version check to Windows
* Improvements

Improve readability of `JavaVersion`
Fix logstash bash script to exit on JavaVersionChecker error

bin/logstash.bat

@@ -47,6 +47,9 @@ if "%MAYBE_JVM_OPTIONS_PARSER_FAILED%" == "jvm_options_parser_failed" (
 )
 set JAVA_OPTS=%LS_JAVA_OPTS%
 
+rem check the Java version
+%JAVA% -cp "%CLASSPATH%" "org.logstash.util.JavaVersionChecker" || exit /b 1
+
 %JAVA% %JAVA_OPTS% -cp "%CLASSPATH%" org.logstash.Logstash %*
 
 goto :end

bin/logstash.lib.sh

@@ -138,6 +138,11 @@ setup_java() {
   export JAVACMD
 
   CLASSPATH="$(setup_classpath $LOGSTASH_JARS)"
+
+  # Verify the version of Java being used, and exit if the wrong version of Java is not available.
+  if ! "${JAVACMD}" -cp "${CLASSPATH}" org.logstash.util.JavaVersionChecker ; then
+    exit 1
+  fi
   JAVA_OPTS=`exec "${JAVACMD}" -cp "${CLASSPATH}" org.logstash.launchers.JvmOptionsParser "$LOGSTASH_HOME" "$LS_JVM_OPTS"`
   unset CLASSPATH
   export JAVA_OPTS

logstash-core/src/main/java/org/logstash/util/JavaVersion.java

@@ -0,0 +1,80 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *	http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.logstash.util;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * Helper class to compare current version of JVM with a target version.
+ * Based on JavaVersion class from elasticsearch java version checker tool
+ */
+public class JavaVersion {
+
+    public static final JavaVersion CURRENT = parse(System.getProperty("java.specification.version"));
+    public static final JavaVersion JAVA_11 = parse("11");
+    private final List<Integer> version;
+
+    private JavaVersion(List<Integer> version){
+        this.version = version;
+    }
+
+    static JavaVersion parse(final String value) {
+        if (value.matches("^0*[0-9]+(\\.[0-9]+)*$") == false) {
+            throw new IllegalArgumentException(value);
+        }
+
+        final List<Integer> version = new ArrayList<Integer>();
+        final String[] components = value.split("\\.");
+        for (final String component : components) {
+            version.add(Integer.valueOf(component));
+        }
+        return new JavaVersion(version);
+    }
+
+    public static int majorVersion(final JavaVersion javaVersion) {
+        Objects.requireNonNull(javaVersion);
+        if (javaVersion.version.get(0) > 1) {
+            return javaVersion.version.get(0);
+        } else {
+            return javaVersion.version.get(1);
+        }
+    }
+
+    public static int compare(final JavaVersion leftVersion, final JavaVersion rightVersion) {
+        List<Integer> left = leftVersion.version;
+        List<Integer> right = rightVersion.version;
+        // lexicographically compare two lists, treating missing entries as zeros
+        final int len = Math.max(left.size(), right.size());
+        for (int i = 0; i < len; i++) {
+            final int l = (i < left.size()) ? left.get(i) : 0;
+            final int r = (i < right.size()) ? right.get(i) : 0;
+            if (l < r) {
+                return -1;
+            }
+            if (r < l) {
+                return 1;
+            }
+        }
+        return 0;
+    }
+
+}

logstash-core/src/main/java/org/logstash/util/JavaVersionChecker.java

@@ -0,0 +1,73 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *	http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.logstash.util;
+
+import java.util.Arrays;
+import java.util.Locale;
+
+/**
+ * Simple program that checks if the runtime Java version is at least 11.
+ * Based on JavaVersionChecker from Elasticsearch
+ */
+final class JavaVersionChecker {
+
+    private JavaVersionChecker() {}
+
+    /**
+     * The main entry point. The exit code is 0 if the Java version is at least 11, otherwise the exit code is 1.
+     *
+     * @param args the args to the program which are rejected if not empty
+     */
+    public static void main(final String[] args) {
+        // no leniency!
+        if (args.length != 0) {
+            throw new IllegalArgumentException("expected zero arguments but was " + Arrays.toString(args));
+        }
+        if (JavaVersion.compare(JavaVersion.CURRENT, JavaVersion.JAVA_11) < 0) {
+            final String message = String.format(
+                    Locale.ROOT,
+                    "the minimum required Java version is 11; your Java version from [%s] does not meet this requirement",
+                    System.getProperty("java.home")
+            );
+            errPrintln(message);
+            exit(1);
+        }
+        exit(0);
+    }
+
+    /**
+     * Prints a string and terminates the line on standard error.
+     *
+     * @param message the message to print
+     */
+    static void errPrintln(final String message) {
+        System.err.println(message);
+    }
+
+    /**
+     * Exit the VM with the specified status.
+     *
+     * @param status the status
+     */
+    static void exit(final int status) {
+        System.exit(status);
+    }
+
+}