Runtime.getRuntime().exec(param) problema

public boolean mapDrive(String drive, String terminal,String partition, String user)
	{
		String command = null;
		command = "net use " + drive + ": \\\\" + terminal +"\\"+partition +" /user:" + user+ " /persistent:no";
		return runCommandToBoolean(command);
	}

      public static String runCommand(String param)
	{
		try
		{
			StringBuffer sb = new StringBuffer();
			Process process = Runtime.getRuntime().exec(param);
			InputStream standardInput = process.getInputStream();
			BufferedReader br = new BufferedReader(new InputStreamReader(standardInput));
			InputStream standardError = process.getErrorStream();
			BufferedReader brError = new BufferedReader(new InputStreamReader(standardError));
			//OutputStream standardOutput = process.getOutputStream();
			String s;

			while ((s = br.readLine()) != null)
			{
				sb.append(s + "\r \n");
			}

			while ((s = brError.readLine()) != null)
			{
				sb.append(s + "\r \n");
			}

			standardInput.close();
			standardError.close();
			return sb.toString();
		}
		catch (Exception e)
		{
			System.out.println(e);
			return null;
		}
	}

public Boolean disconnectDrive(String drive)
	{
		String command = "net use /delete "+drive+":";
		if (runCommandToBoolean(command)==false)
                {
                    System.out.println("Não conseguiu desligar ");
                    
                }
                return true;
	}