You can use Apache Commons exec library also.

Example :

package testShellScript;

import java.io.IOException;
import org.apache.commons.exec.CommandLine;
import org.apache.commons.exec.DefaultExecutor;
import org.apache.commons.exec.ExecuteException;

public class TestScript {
    int iExitValue;
    String sCommandString;

    public void runScript(String command){
        sCommandString = command;
        CommandLine oCmdLine = CommandLine.parse(sCommandString);
        DefaultExecutor oDefaultExecutor = new DefaultExecutor();
        oDefaultExecutor.setExitValue(0);
        try {
            iExitValue = oDefaultExecutor.execute(oCmdLine);
        } catch (ExecuteException e) {
            System.err.println("Execution failed.");
            e.printStackTrace();
        } catch (IOException e) {
            System.err.println("permission denied.");
            e.printStackTrace();
        }
    }

    public static void main(String args[]){
        TestScript testScript = new TestScript();
        testScript.runScript("sh /root/Desktop/testScript.sh");
    }
}

For further reference, An example is given on Apache Doc also.

Note: You should use ProcessBuilder to launch as it provides better control over I/O streams, and the Runtime.exec call you use is deprecated. However the outcome would be the same in your case.

The issue here is that bash on Windows is expecting a Linux style pathname, and you are passing in Windows OS pathname.

Your Path environment for bash.exe is correct because you don't get IOException : Cannot run program "bash.exe": CreateProcess error=2, The system cannot find the file specified.

Thus bash.exe has run, but it reports exit code 127 which means Command not found, or PATH error. To fix you need to form valid GNU/Linux pathname to the script. If you are using WSL the C drive is mapped as "/mnt/c" so you need to run the translated path:

String[] cmd = new String[]{ "bash.exe", "/mnt/c/Users/abc/Downloads/test.sh" };

// Using "bash" above should also work if "bash.exe" is in the Path and PATHEXT contains ".EXE"
Process p = new ProcessBuilder(cmd).redirectErrorStream(true).start();
p.getInputStream().transferTo(System.out);
System.out.println(p.waitFor());

You could avoid the OS pathname translation by using a relative path to the script and run from it's directory:

File exe = new File("C:\\Users\\abc\\Downloads\\test.sh");
// Set up relative path for the script
String[] cmd = new String[]{"bash", exe.getName()};

ProcessBuilder pb = new ProcessBuilder(cmd).redirectErrorStream(true);
// Run from the directory of the script:
pb.directory(exe.getParentFile());
Process p = pb.start();
p.getInputStream().transferTo(System.out);
System.out.println(p.waitFor());

Thanks everybody for your responses. I found a solution to the problem. For this kind of situation we need to bind my Windows machine to Linux system. Here is the code that worked:

Copypublic String executeSHFile(String Username, String Password,String  Hostname)
    {
        String hostname = Hostname;
        String username = Username;
        String password = Password;
        try{
            Connection conn = new Connection(hostname);
               conn.connect();
               boolean isAuthenticated = conn.authenticateWithPassword(username, password);
               if (isAuthenticated == false)
                throw new IOException("Authentication failed.");
               Session sess = conn.openSession();
              sess.execCommand("sh //full path/file name.sh");

               System.out.println("Here is some information about the remote host:");
               InputStream stdout = new StreamGobbler(sess.getStdout());
               BufferedReader br = new BufferedReader(new InputStreamReader(stdout));
               while (true)
                {
                    String line = br.readLine();
                    if (line == null)
                        break;
                    current_time=line;
                    System.out.println(line);
                }

               System.out.println("ExitCode: " + sess.getExitStatus());
               /* Close this session */

                sess.close();

                /* Close the connection */

                conn.close();
        }catch(IOException e)
        {
            e.printStackTrace(System.err);
            System.exit(2);
        }finally{

        }
}

Thank you.

Also consider ExpectJ which is a wrapper around TCL Expect. The project does not appear to have any active development since mid 2010, but I have used it for SSH in the past.

http://expectj.sourceforge.net/apidocs/expectj/SshSpawn.html