Get Java version of specified directory.

CheckJavaVersion.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Text.RegularExpressions;

namespace CheckJavaVersion {
    class Program {
        static void Main(string[] args) {

            var cjv = new CheckJavaVersion();

            var paths = new List<string> {
                @"C:\Program Files\Java\jdk1.8.0_91",
                @"C:\Program Files\Java\jdk1.8.0_91\jre",
                @"C:\Program Files\Java\jdk1.8.0_91\bin",
                @"C:\Program Files\Java\jre1.8.0_91\bin",
                @"C:\Program Files (x86)\Java\jdk1.7.0_55",
                @"J:\opt\JetBrains\IntelliJ IDEA 2016.2.3\jre\jre",
                @"D:\usr\local\pleiades_juno\java\6",
                @"D:\usr\local\pleiades_juno\java\7",
                @"C:\usr\local\pleiades\java\6",
                @"C:\pleiades\java\7",
                @"C:\Go",
                @"c:\windows",
                @"c:\nothingdirectory",
                @"S:\nothingrive",
            };

            paths.ForEach(x => {
                var result = cjv.GetVersion(x);

                if (string.IsNullOrEmpty(result)) {
                    Console.WriteLine("Can't find");
                }
                else {
                    Console.WriteLine(result);
                }
            });

            Console.ReadKey();
        }
    }


    class CheckJavaVersion {
        public string GetVersion(string path) {
            if (string.IsNullOrEmpty(path)) return null;
            if (!Directory.Exists(path)) return null;

            var javaPath = "";
            if (File.Exists(Path.Combine(path, "java.exe"))) {
                javaPath = Path.Combine(path, "java.exe");
            }
            else if(File.Exists(Path.Combine(path, "bin", "java.exe"))){
                javaPath = Path.Combine(path, "bin", "java.exe");
            }

            if (javaPath == "") return null;

            var psi = new ProcessStartInfo(javaPath, "-version");
            psi.RedirectStandardError = true;
            psi.UseShellExecute = false;
            psi.CreateNoWindow = true;
            var p = Process.Start(psi);
            var stdOut = p.StandardError.ReadLine();
            p.StandardError.ReadToEnd();
            p.Close();

            var m = Regex.Match(stdOut, "^.*?(java|openjdk) version \"([0-9])\\.([0-9]+)(.*?)\".*$");

            return m.Groups[2] + "." + m.Groups[3] + ", " + m.Groups[2] + "." + m.Groups[3] + m.Groups[4] + ", " + m.Groups[1];
        }
    }
}

sample output

1.8, 1.8.0_91, java
1.8, 1.8.0_91, java
1.8, 1.8.0_91, java
1.8, 1.8.0_91, java
1.7, 1.7.0_55, java
1.8, 1.8.0_112-release, openjdk
1.6, 1.6.0_41, java
1.7, 1.7.0_15, java
1.6, 1.6.0_45, java
1.7, 1.7.0_67, java
Can't find
Can't find
Can't find
Can't find