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JavaVersionChecker.java
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JavaVersionChecker.java
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/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.tools.java_version_checker;
import java.util.Arrays;
import java.util.Locale;
/**
* Simple program that checks if the runtime Java version is at least 1.8.
*/
final class JavaVersionChecker {
private JavaVersionChecker() {}
/**
* The main entry point. The exit code is 0 if the Java version is at least 1.8, 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_8) < 0) {
final String message = String.format(
Locale.ROOT,
"the minimum required Java version is 8; your Java version from [%s] does not meet this requirement",
System.getProperty("java.home")
);
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);
}
/**
* Prints a string and terminates the line on standard error.
*
* @param message the message to print
*/
@SuppressForbidden(reason = "System#err")
static void errPrintln(final String message) {
System.err.println(message);
}
/**
* Exit the VM with the specified status.
*
* @param status the status
*/
@SuppressForbidden(reason = "System#exit")
static void exit(final int status) {
System.exit(status);
}
}