JAVA中获取安装路径、运行路径、执行路径的办法

　　这些路径意思听起来很糊涂，对不对？这很正常，大家都这样。怎么办？开发中把下列参数进行修改，看结果是不是自己期望的那个：

    /**
     * java.version         Java version number
     * java.vendor          Java vendor specific string
     * java.vendor.url      Java vendor URL
     * java.home            Java installation directory
     * java.class.version   Java class version number
     * java.class.path      Java classpath
     * os.name              Operating System Name
     * os.arch              Operating System Architecture
     * os.version           Operating System Version
     * file.separator       File separator ("/" on Unix)
     * path.separator       Path separator (":" on Unix)
     * line.separator       Line separator ("\n" on Unix)
     * user.name            User account name
     * user.home            User home directory
     * user.dir             User's current working directory
     */

System.out.println("java.home="+System.getProperty("java.home"));