test/jdk/sun/security/tools/jarsigner/compatibility/JdkUtils.java

/*
 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

import java.security.NoSuchAlgorithmException;
import java.security.Signature;

/*
 * This class is used for returning some specific JDK information.
 */
public class JdkUtils {

    static final String M_JAVA_RUNTIME_VERSION = "javaRuntimeVersion";
    static final String M_IS_SUPPORTED_SIGALG = "isSupportedSigalg";

    // Returns the JDK build version.
    static String javaRuntimeVersion() {
        return System.getProperty("java.runtime.version");
    }

    // Checks if the specified signature algorithm is supported by the JDK.
    static boolean isSupportedSigalg(String sigalg) {
        boolean isSupported = false;
        try {
            isSupported = Signature.getInstance(sigalg) != null;
        } catch (NoSuchAlgorithmException e) { }

        if (!isSupported) {
            System.out.println(sigalg + " is not supported yet.");
        }

        return isSupported;
    }

    public static void main(String[] args) {
        if (M_JAVA_RUNTIME_VERSION.equals(args[0])) {
            System.out.print(javaRuntimeVersion());
        } else if (M_IS_SUPPORTED_SIGALG.equals(args[0])) {
            System.out.print(isSupportedSigalg(args[1]));
        }
    }
}