1 /*
   2  * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 import java.security.NoSuchAlgorithmException;
  25 import java.security.Signature;
  26 
  27 /*
  28  * This class is used for returning some specific JDK information.
  29  */
  30 public class JdkUtils {
  31 
  32     static final String M_JAVA_RUNTIME_VERSION = "javaRuntimeVersion";
  33     static final String M_IS_SUPPORTED_SIGALG = "isSupportedSigalg";
  34 
  35     // Returns the JDK build version.
  36     static String javaRuntimeVersion() {
  37         return System.getProperty("java.runtime.version");
  38     }
  39 
  40     // Checks if the specified signature algorithm is supported by the JDK.
  41     static boolean isSupportedSigalg(String sigalg) {
  42         boolean isSupported = false;
  43         try {
  44             isSupported = Signature.getInstance(sigalg) != null;
  45         } catch (NoSuchAlgorithmException e) { }
  46 
  47         if (!isSupported) {
  48             System.out.println(sigalg + " is not supported yet.");
  49         }
  50 
  51         return isSupported;
  52     }
  53 
  54     public static void main(String[] args) {
  55         if (M_JAVA_RUNTIME_VERSION.equals(args[0])) {
  56             System.out.print(javaRuntimeVersion());
  57         } else if (M_IS_SUPPORTED_SIGALG.equals(args[0])) {
  58             System.out.print(isSupportedSigalg(args[1]));
  59         }
  60     }
  61 }