exec() - Executing Operating System Commands

Java Tutorials - Herong's Tutorial Examples

∟System Properties and Runtime Object Methods

∟exec() - Executing Operating System Commands

This section provides a tutorial example on how to calculate memory usage of a large array.

The Runtime instance also offers methods for the Java application program to execute an operating system command as a subprocess. The following program uses the exec() method to execute "chkdsk" command:

/* CheckDisk.java
 * Copyright (c) HerongYang.com. All Rights Reserved.
 */
import java.io.*;
public class CheckDisk {
   private static String cmd = "C:\\Windows\\System32\\chkdsk f:";
   public static void main(String[] a) {
      Runtime rt = Runtime.getRuntime();
      try {
         Process p = rt.exec(cmd);
         Reader in = new InputStreamReader(p.getInputStream());
         int c = in.read();
         while (c!=-1) {
            System.out.print((char)c);
            c = in.read();
         }
      } catch (IOException e) {
         System.out.println(e.toString());
      }
   }
}

Note that the program assumes that you have a storage device connected as drive F:.

Output:

The type of the file system is FAT.
Volume UDISK 2.0 created 6/8/2018 10:10 PM
Windows is verifying files and folders...
File and folder verification is complete.
Windows has checked the file system and found no problems.

  259,756,032 bytes total disk space.
       16,384 bytes in 4 folders.
    9,371,648 bytes in 15 files.
  250,368,000 bytes available on disk.

        4,096 bytes in each allocation unit.
       63,417 total allocation units on disk.
       61,125 allocation units available on disk.