From what I understand you are trying to invoke a command from within your java program to do something and then return to your java program again. If so:
*snip*
1: String command = "Shutdown.exe -r -t 00";
2: System(command);
3: //System.in(command); ??!
*snip*
I can't seem to understand what you are doing in the second line. Unless you wrote a method called System that is static, then I don't think the compiler will let you do what you've entered in line two above. From what I gather you are trying to call a System method, b/c there was a method in C that was called system that performed similar operations; this is very rarely the case. C standard functions don't map exactly to java methods.
Also AFAIK the System class doesn't have a constructor, and that is not the method to initialiaze a new occurence of an Object. All of the methods in the System class I have used have been static, so an instance of System object isn't even required. Maybe some comments in your code will give a better picture of what you intend.
Take a look at Runtime class in the APIs; java.lang.Runtime. I will let you figure out the finer details, but here are some hints;
1. You need a Runtime object, so found out how you can create/get an instance of the Object.
2. What method you have to call on the Runtime object so that it executes your command.
3. (optional) how to get input, output from the execute program invoked by your command and the exit code (just in case you need to see whether it terminated gracefully or whether there was an error).
Another hint: the system might not be able to find the command you are executing. You can usually find out by going to run and entering the command.
Hope that helps. Post if you have any further problems or if you can't decipher my cryptic explanation.