Calling java host command in trigger/PLSQL

Question

I created a java call to execute a linux host command that calls a shell script that will echo out a result. It is owned by SYS and has granted execute to SYSTEM. SYSTEM has a table that monitors accesses to the RDBMS. When a user logs on from a remote server vis sqlplus, this LOGON trigger write to the SYSTEM table (successfully). SYSTEM has a trigger that runs a linux command to execute a shell script that pulls the actual IP address from the remote system. I can run this call from a PLSQL block (outside the trigger) and get a response back like "user:101.101.101.111" but when I have the same user log on, the trigger fires - no errors or exceptions yet no rows are returned. Is there some restriction in a trigger versus just a plsql block call? The java code used is what I found on (http://www.oracle-base.com/articles/8i/ ... mPLSQL.php) and it works perfectly OUTSIDE the trigger but nothing is returned in the trigger firing steps. Any idea?
rdbms: 11.1.0.7, Redhat 4
I know the code works because I can write the host command output to a file. Later in the trigger I can open the file and can read the data that should have been returned in the java host call.

Answer 1

FYI - here is the code from your site that I used:
DROP JAVA SOURCE SYS."Host";
CREATE OR REPLACE AND RESOLVE JAVA SOURCE NAMED SYS."Host" as import java.io.*;
public class Host {
public static void executeCommand(String command) {
try {
String[] finalCommand;
if (isWindows()) {
finalCommand = new String[4];
// Use the appropriate path for your windows version.
finalCommand[0] = "C:\\windows\\system32\\cmd.exe"; // Windows XP/2003
//finalCommand[0] = "C:\\winnt\\system32\\cmd.exe"; // Windows NT/2000
finalCommand[1] = "/y";
finalCommand[2] = "/c";
finalCommand[3] = command;
else {
finalCommand = new String[3];
finalCommand[0] = "/bin/sh";
finalCommand[1] = "-c";
finalCommand[2] = command;
final Process pr = Runtime.getRuntime().exec(finalCommand);
pr.waitFor();
new Thread(new Runnable(){
public void run() {
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("Cmd results: " + buff);
try {Thread.sleep(100); } catch(Exception e) {}
br_in.close();
catch (IOException ioe) {
System.out.println("Exception caught printing process output.");
ioe.printStackTrace();
finally {
try {
br_in.close();
} catch (Exception ex) {}
}).start();
new Thread(new Runnable(){
public void run() {
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("Cmd Error: " + buff);
try {Thread.sleep(100); } catch(Exception e) {}
br_err.close();
catch (IOException ioe) {
System.out.println("Exception caught printing process error.");
ioe.printStackTrace();
finally {
try {
br_err.close();
} catch (Exception ex) {}
}).start();
catch (Exception ex) {
System.out.println(ex.getLocalizedMessage());
public static boolean isWindows() {
if (System.getProperty("os.name").toLowerCase().indexOf("windows") != -1)
return true;
else
return false;
/