EXEC dbms_java.grant_permission('ABC', 'SYS:java.lang.RuntimePermission', 'writeFileDescriptor', '');
EXEC dbms_java.grant_permission('ABC', 'SYS:java.lang.RuntimePermission', 'readFileDescriptor', '');
EXEC dbms_java.grant_permission('ABC', 'SYS:java.io.FilePermission', '/bin/sh', 'execute');

And then, login to ABC and create java in sqlplus:

CREATE OR REPLACE AND COMPILE JAVA SOURCE NAMED "Host" AS
import java.io.*;
public class Host {
  public static void executeCommand(String command) {
    try {
      String[] finalCommand;
      if (System.getProperty("os.name").toLowerCase().indexOf("windows") != -1) {
        finalCommand = new String[4];
        finalCommand[0] = "C:\\winnt\\system32\\cmd.exe";
        finalCommand[1] = "/y";
        finalCommand[2] = "/c";
        finalCommand[3] = command;
      } else {
	// Linux or Unix System
        finalCommand = new String[3];
        finalCommand[0] = "/bin/sh";
        finalCommand[1] = "-c";
        finalCommand[2] = command;
      }

      // Execute the command...
      final Process pr = Runtime.getRuntime().exec(finalCommand);

      // Capture output from STDOUT...
      BufferedReader br_in = null;
      try {
        br_in = new BufferedReader(
            new InputStreamReader(pr.getInputStream()));
        String buff = null;
        while ((buff = br_in.readLine()) != null) {
          System.out.println("stdout: " + buff);
          try {Thread.sleep(100); } catch(Exception e) {}
        }
        br_in.close();
      } catch (IOException ioe) {
        System.out.println("Error printing process output.");
        ioe.printStackTrace();
      } finally {
        try {
          br_in.close();
        } catch (Exception ex) {}
      }

      // Capture output from STDERR...
      BufferedReader br_err = null;
      try {
        br_err = new BufferedReader(
            new InputStreamReader(pr.getErrorStream()));
        String buff = null;
        while ((buff = br_err.readLine()) != null) {
          System.out.println("stderr: " + buff);
          try {Thread.sleep(100); } catch(Exception e) {}
        }
        br_err.close();
      } catch (IOException ioe) {
        System.out.println("Error printing execution errors.");
        ioe.printStackTrace();
      } finally {
        try {
          br_err.close();
        } catch (Exception ex) {}
      }
    }
    catch (Exception ex) {
      System.out.println(ex.getLocalizedMessage());
    }
  }
};

after that, create procedure in sqlplus:

CREATE OR REPLACE PROCEDURE host (p_command IN VARCHAR2)
   AS LANGUAGE JAVA
   NAME 'Host.executeCommand (java.lang.String)';

set the output display if neccessary in sqlplus:

CALL DBMS_JAVA.SET_OUTPUT(1000000);
SET SERVEROUTPUT ON

You can test the procedure using following command:

exec host('/bin/ls');

Create a sh file in linux:

#!/bin/bash
source /home/abc/.bash_profile
cd /home/abc
java -jar /home/abc/abc.jar

Remember to change mode in linux:

chmod a+x /home/abc/run.sh

Finally, create the trigger:

create or replace trigger abc_run
after update on abc.testing
begin host('/home/abc/run.sh');
end;

commit;

Reference: Ref1 Ref2

host ls -l

or

!ls -l

Dummy Table Name: dual

Get user error message in oracle:

select * from user_errors;

or

show errors;

ERROR: PLS-00201: identifier ‘SYS.DBMS_PIPE’ must be declared
Connect to the SYS schema and issue the following command:

grant all on dbms_pipe to public;