clients/src/main/java/org/apache/kafka/common/utils/Java.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF 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.apache.kafka.common.utils;

import java.util.StringTokenizer;

public final class Java {

    private Java() { }

    private static final Version VERSION = parseVersion(System.getProperty("java.specification.version"));

    // Package private for testing
    static Version parseVersion(String versionString) {
        final StringTokenizer st = new StringTokenizer(versionString, ".");
        int majorVersion = Integer.parseInt(st.nextToken());
        int minorVersion;
        if (st.hasMoreTokens())
            minorVersion = Integer.parseInt(st.nextToken());
        else
            minorVersion = 0;
        return new Version(majorVersion, minorVersion);
    }

    // Having these as static final provides the best opportunity for compilar optimization
    public static final boolean IS_JAVA9_COMPATIBLE = VERSION.isJava9Compatible();

    public static boolean isIbmJdk() {
        return System.getProperty("java.vendor").contains("IBM");
    }

    // Package private for testing
    static class Version {
        public final int majorVersion;
        public final int minorVersion;

        private Version(int majorVersion, int minorVersion) {
            this.majorVersion = majorVersion;
            this.minorVersion = minorVersion;
        }

        @Override
        public String toString() {
            return "Version(majorVersion=" + majorVersion +
                    ", minorVersion=" + minorVersion + ")";
        }

        // Package private for testing
        boolean isJava9Compatible() {
            return majorVersion >= 9;
        }

    }

}