步骤:

1.)在谷歌上搜索“Java SE Runtime Environment”:https://www.google.com/search?q=Java+SE+Runtime+Environment

2.)在你的电脑上安装合适的版本

除了所有其他的建议，还有一件事你需要考虑。你的helloworld.jar是一个控制台程序吗?如果是，那么我不相信您能够将其变成一个可双击的jar文件。控制台程序使用常规的cmd.exe shell窗口作为它们的输入和输出。通常jar“启动器”绑定到javaw.exe，它不会创建命令shell窗口。

我正在运行Windows 7 x64，无法使用任何这些修复程序。

这条对我来说还是有用的:

http://thepanz.netsons.org/post/windows7-jar-file-association-broken-with-nokia-ovi

你可以下载一个包含要运行的.bat文件的存档文件，但请检查实际的javaw.exe!!!!的路径

事实上，我也遇到过这个问题。我通过为我的jar文件创建.bat运行程序来解决这个问题。

代码如下:

class FileHandler{
   public static File create_CMD_Rnner(){
      int exitCode = -1625348952;
      try{
           File runner = new File(Main.batName);
           PrintWriter printer = new PrintWriter(runner);
           printer.println("@echo off");
           printer.println("title " + Main.applicationTitle);
           printer.println("java -jar " + Main.jarName + " " + Main.startCode );
           printer.println("PAUSE");
           printer.flush();
           printer.close();
           return runner;
       }catch(Exception e){
           System.err.println("Coudln't create a runner bat \n exit code: " + exitCode);
           System.exit(exitCode);
           return null;
       }
   }
}

然后在你的主应用程序类中这样做:

public class Main{
    static String jarName = "application.jar";
    static String applicationTitle = "java Application";
    static String startCode = "javaIsTheBest";
    static String batName = "_.bat";


    public static void main(String args[]) throws Exception{
        if(args.length == 0 || !args[0].equals(startCode)) {
            Desktop.getDesktop().open(FilesHandler.create_CMD_Rnner());
            System.exit(0);
        }else{
            //just in case you wanted to hide the bat
            deleteRunner();
            // Congratulations now you are running in a cmd window ... do whatever you want
            //......
            System.out.println("i Am Running in CMD");
            //......
            Thread.sleep(84600);
        }
    }


    public static void deleteRunner(){
        File batRunner = new File(batName);
        if(batRunner.exists()) batRunner.delete();
    }
}

请注意

这段代码(我的代码)只适用于jar文件，而不是类文件。 jar文件必须与Main类的字符串“jarName”同名

最简单的方法可能是升级或重新安装Java运行时环境(JRE)。

或:

Open the Windows Explorer, from the Tools select 'Folder Options...' Click the File Types tab, scroll down and select JAR File type. Press the Advanced button. In the Edit File Type dialog box, select open in Actions box and click Edit... Press the Browse button and navigate to the location the Java interpreter javaw.exe. In the Application used to perform action field, needs to display something similar to C:\Program Files\Java\j2re1.4.2_04\bin\javaw.exe" -jar "%1" % (Note: the part starting with 'javaw' must be exactly like that; the other part of the path name can vary depending on which version of Java you're using) then press the OK buttons until all the dialogs are closed.

这是从这里偷来的:http://windowstipoftheday.blogspot.com/2005/10/setting-jar-file-association.html

首先在cmd(命令提示符)上设置路径:

set path="C:\Program Files\Java\jre6\bin"

然后输入

java -jar yourProgramname.jar