How to restart computer using simple java program

i have a code for shut down how is restart and hibernate can be done
code is
import java.util.*;
import java.io.*;
public class BadExecJavac
     public static void main(String args[])
     try
          Runtime rt = Runtime.getRuntime();
          Process proc = rt.exec("shutdown -t 10");
     }catch (Exception e)
          System.out.print(e);
}

I hope your app is first asking the user for
permission to do that first. Otherwise be prepared to
be smacked upside the head with a smelly sock when
you reboot when the user really really really didn't
want you to.I'm actually counting on natural selection to do its work in this case. That's why I was willing to help.

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How to restart windows (any) from java program

What is the system program that I have to call in order to restart windows...
Runtime.getRuntime().exec(???);

I hope your app is first asking the user for
permission to do that first. Otherwise be prepared to
be smacked upside the head with a smelly sock when
you reboot when the user really really really didn't
want you to.I'm actually counting on natural selection to do its work in this case. That's why I was willing to help.

How to use another java program to stop this running prpgram???

Dear Sir:
I have following code and I run it success,
import java.util.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.*;
public class CertainAndRepeatTime{
public static void main(String[] args) throws IOException{
    int delay = 1;
    Timer timer = new Timer();
    ActionListener actionListener = new ActionListener() {
        public void actionPerformed(ActionEvent actionEvent) {
          System.out.println("Hello World Timer");
    System.out.println("What do you want (Certain time or Repeat time)?");
    System.out.print("Please enter \'C\' or \'R\' for that: ");
    BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    String ans = in.readLine();
    System.out.print("Please enter ans=" + ans + " IsTrue= " + (ans.equals("R") || ans.equals("r")) +"\n");
    if (ans.equals("C") || ans.equals("c")){
      //System.out.println("This line is printed only once start...");
      timer.schedule(new TimerTask(){
        public void run(){
          System.out.println("This line is printed only once.");
      },delay,1);
    else if(ans.equals("r") || ans.equals("R")){
        timer.scheduleAtFixedRate(new TimerTask(){
          public void run(){
            System.out.println("This line is printed repeatedly.");
        },delay, 1000);
      while(true){
           //System.out.println("Charles print This line is printed repeatedly.");
      } //This will make your main thread hang.
    else{
      System.out.println("Invalid Entry.");
      System.exit(0);
    System.exit(0);
}But I hope to use another java program to stop it when it is running instead of pressing CRTL + C to stop it.
How to do it??
Any example??
Thanks a lot!!

Sorry, I think i did not express cearly. It is my fault.
I re-write my requirements again:
I have
Class AAA1.java,
Class AAA2.java,
Class AAA3.java,
Class AAA20.java...
etc
they all look like the program I posted first time,, once executed, they will run for ever, and they will be stopped until I press CRTL + C;
Now I hope to use another java class StopProgram.java to stop them 1 by 1 or at once instead of pressing CRTL + C;
In this case, how to code this StopProgram.java ??
Thanks

How to find out jre version installed ,using a java program?

Hello,
Is there any way to find out the installed JRE version using a java program ?
The requirement is as follows:
There is a html page with 4 steps to install a software. each step is a link, which upon clicking does its work.
the first step is to install jre 1.4.2_11 if its not installed in the system. But how can i find out whether jre 1.4.2_11 is installed or not ?
Thanks in advance

For the hell of it... here is a list of properties you can query:
java.version Java Runtime Environment version
java.vendor Java Runtime Environment vendor
java.vendor.url Java vendor URL
java.home Java installation directory
java.vm.specification.version Java Virtual Machine specification version
java.vm.specification.vendor Java Virtual Machine specification vendor
java.vm.specification.name Java Virtual Machine specification name
java.vm.version Java Virtual Machine implementation version
java.vm.vendor Java Virtual Machine implementation vendor
java.vm.name Java Virtual Machine implementation name
java.specification.version Java Runtime Environment specification version
java.specification.vendor Java Runtime Environment specification vendor
java.specification.name Java Runtime Environment specification name
java.class.version Java class format version number
java.class.path Java class path
java.library.path List of paths to search when loading libraries
java.io.tmpdir Default temp file path
java.compiler Name of JIT compiler to use
java.ext.dirs Path of extension directory or directories
os.name Operating system name
os.arch Operating system architecture
os.version Operating system version
file.separator File separator ("/" on UNIX)
path.separator Path separator (":" on UNIX)
line.separator Line separator ("\n" on UNIX)
user.name User's account name
user.home User's home directory
user.dir User's current working directory

How to export crystal report into disk using simple java

hello
i m working in the reporting part my j2ee application
my requirement is that export this rpt file into pdf file and store into disk by writing simple java program
if any have code this then plz provide me
thanks & regards
ram

Uhm, these messages are not that related. One's a
JNDI problem, this one's just some vague "how do I
do" stuff.He wants to produce something in crystal reports and turn it into a PDF. So yes they are related. And yet another thread for this just sprung up.

How to find out internet explorer version ,using a java program?

How to find out internet explorer version ,using a java program?

Browser version from java?....you must be referring it from some web application....rite?
You can read the User-Agent header using request.getUserAgent() or request.getHeader("User-Agent") in your jsp or servlet.
for more details pls refer:
http://www.jguru.com/jguru/faq/view.jsp?EID=12253

How can i use this java program to access from a jsp page?

import java.io.*;
import java.util.*;
public class FileProcessing
//create a vector container for the input variables
     Vector variables = new Vector();
//create a vector container for the constants
     Vector constants = new Vector();
/*create a string expression container for the equation
     as read from the file */
     String expression = " ";
//create double result container for the final result
     double result = 0;
     public boolean processFile(String filename,String delim)
      //index for values vector
          int num_values = 0;
      //index for constants vector
          int num_constants = 0;
      //current line being read from the external file.
          String curline = " ";
      //start reading from the external file
          try
               FileReader fr = new FileReader(filename);
               BufferedReader br = new BufferedReader(fr);
               while(true)
                    curline = br.readLine();
                    if(curline == null)
                         break;
                //determine the type of current interaction
                    boolean variable = curline.startsWith("input");
                    boolean constant = curline.startsWith("constant");
                    boolean equation = curline.startsWith("equation");
                    boolean output = curline.startsWith("result");
               //on input variables
                    if(variable)
                      StringTokenizer st = new StringTokenizer(curline,delim);
                      int num = st.countTokens();
                      int count=0;
                      while(st.hasMoreTokens())
                           String temp = st.nextToken();
                           if(count==1)
                                byte b[]= new byte[100];
                                System.out.println(temp);
                                System.in.read(b);
                                String inputval = (new String(b)).trim();
                                variables.add(num_values,inputval);
                                num_values++;
                           count++;
                    // on constant values
                    if(constant)
                         StringTokenizer st = new StringTokenizer(curline,delim);
                         int num = st.countTokens();
                         int count = 0;
                         while(st.hasMoreTokens())
                              String temp = st.nextToken();
                              if(count==1)
                                   byte b[]= new byte[100];
                                   System.out.println(temp);
                                   System.in.read(b);
                                   String cons = (new String(b)).trim();
                                   constants.add(num_constants,cons);
                                   num_constants++;
                              count++;
                    // on equation
                    if(equation)
                         StringTokenizer st = new StringTokenizer(curline,delim);
                         int num = st.countTokens();
                         int count = 0;
                         while(st.hasMoreTokens())
                              String temp = st.nextToken();
                              if(count==2)
                                   this.expression = temp;
                              count++;
          // now we are ready to evaluate the expression
                   if(output)
                      org.nfunk.jep.JEP myparser= new org.nfunk.jep.JEP();
                      myparser.setAllowAssignment(true);
                      for(int i=1;i<variables.size()+1;i++)
                         String name = "arg"+Integer.toString(i);
                         myparser.addVariable(name,new Double(variables.get(i-1)
                                            .toString()).doubleValue());
                      for(int i=1;i<constants.size()+1;i++)
                           String name = "arg" +Integer.
                                     toString(i+variables.size());
                           myparser.addConstant(name,new Double(constants.get(i-1).toString()));
               //output is obtained as follows
                      myparser.parseExpression(expression);
                      result = myparser.getValue();
                      System.out.println("Assay value: "+result);
          catch(Exception e)
               System.out.println(e.toString());
          return true;
     public static void main(String[] args)
          FileProcessing fp = new FileProcessing();
          fp.processFile("input.eqn",":");
}here i need to generate the strings like 'enter value1' and respective text boxes dynamically . i should use this java program as business logic and a jsp page for view.
following given is my text file input.eqn
input:enter value1:arg1
input:enter value2:arg2
input:enter value3:arg3
constant:enter constant1:arg4
constant:enter constant2:arg5
equation:enter equation:(arg1+arg2)*(arg3+arg4)*arg5
result:

Why do you double post ? http://forum.java.sun.com/thread.jspa?threadID=646988&tstart=0
Why dint that answer satisfy you ? And why dint you say so in that thread rather than posting the same question again ?
ram.

How to find out internet version ,using a java program?

Can any one send javacode to find out the internet version ,using a java program?

i mean internet explorer version
Edited by: mvasu on Feb 20, 2008 2:04 AM

A simple Java program to be compiled with ojc and executed with java.exe

Hi ,
This thread is relevant to Oracle Java Compiler (file ojc) and jave.exe file.
I have written a simple java program which consists of two simple simple classes and using the JDev's 10.1.3.2 ojc and java files , i'm trying to execute it after the successful compilation....
The problem is that trying to run it... the error :
Exception in thread "main" java.lang.NoClassDefFoundError: EmployeeTest
appears.
How can i solve this problem...????
The program is as follows:
import java.util.*;
import corejava.*;
public class EmployeeTest
{ public static void main(String[] args)
   { Employee[] staff = new Employee[3];
      staff[0] = new Employee("Harry Hacker", 35000,
         new Day(1989,10,1));
      staff[1] = new Employee("Carl Cracker", 75000,
         new Day(1987,12,15));
      staff[2] = new Employee("Tony Tester", 38000,
         new Day(1990,3,15));
      int i;
      for (i = 0; i < 3; i++) staff.raiseSalary(5);
for (i = 0; i < 3; i++) staff[i].print();
class Employee
{ public Employee(String n, double s, Day d)
{ name = n;
salary = s;
hireDay = d;
public void print()
{ System.out.println(name + "...." + salary + "...."
+ hireYear());
public void raiseSalary(double byPercent)
{ salary *= 1 + byPercent / 100;
public int hireYear()
{ return hireDay.getYear();
private String name;
private double salary;
private Day hireDay;
For compilation... i use :
D:\ORACLE_UNZIPPED\JDeveloper_10.1.3.2\jdev\bin\ojc -classpath D:\E-Book\Java\Sun_Java_Book_I\Corejava EmployeeTest.java
For execution , i issue the command:
D:\ORACLE_UNZIPPED\JDeveloper_10.1.3.2\jdk\bin\java EmployeeTest
NOTE:I tried to use the jdk of Oracle database v.2 but the error :
Unable to initialize JVM appeared....
Thanks , a lot
Simon

Hi,
Thanks god....
I found a solution without using Jdev.....
C:\oracle_files\Java\Examples>SET CLASSPATH=.;D:\E-Book\Java\Sun_Java_Book_I\Corejava
C:\oracle_files\Java\Examples>D:\ORACLE_UNZIPPED\JDeveloper_10.1.3.2\jdk\bin\javac EmployeeTest.java
C:\oracle_files\Java\Examples>D:\ORACLE_UNZIPPED\JDeveloper_10.1.3.2\jdk\bin\java EmployeeTest
What does Ant has to do with this?Sorry, under the Ant tree a classpath label is found....I'm very new to Java and JDev...
You need to include the jar file that has the Day method in it inside project properties->libraries.I have not .jar file.. just some .java files under the corejava directory.... By the way , I have inserted the corejava directory to the project pressing the button Add Jar/Directory.... , but the problem insists..
Thanks , a lot
Simon

How to change system time through java program

Hi
I want to know, how to change system time through java program.
give me a idia with example.
Thanks

There isn't any core Java API for this. Use JNI or call an external process with Runtime.exec().
~

Opening a project in Eclipse by using a java program from outside..

Hi friends,
I have a java program which will open the Eclipse editor..now i want to open a file , in a specifeid path, in that eclipse. I completed opening the eclipse editor and also i m fetching the file which in a particular path..my problem is i couldnt open that file in eclipse by using my java program..
i donno how to open a particulat file or proj in the eclipse from outside java prog.
thanks,
Krishna

Try this:
Error "This project contained a sequence that could not be opened"

Problem while executing simple java program

Hi
while trying to execute a simple java program,i am getting the following exception...
please help me in this
java program :import java.util.*;
import java.util.logging.*;
public class Jump implements Runnable{
    Hashtable activeQueues = new Hashtable();
    String dbURL, dbuser, dbpasswd, loggerDir;
    int idleSleep;
    static Logger logger = Logger.getAnonymousLogger();
    Thread myThread = null;
    JumpQueueManager manager = null;
    private final static String VERSION = "2.92";
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        dbURL = jdbcURL;
        dbuser = user;
        dbpasswd = pwd;
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        manager = new JumpQueueManager(dbURL, dbuser, dbpasswd);
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        //preparing logger
        prepareLogger();
      private void prepareLogger(){
        Handler hndl = new pl.com.sony.utils.SimpleLoggerHandler();
        try{
            String logFilePattern = loggerDir + java.io.File.separator + "jumplog%g.log";
            Handler filehndl = new java.util.logging.FileHandler(logFilePattern, JumpConstants.MAX_LOG_SIZE, JumpConstants.MAX_LOG_FILE_NUM);
            filehndl.setEncoding("UTF-8");
            filehndl.setLevel(Level.INFO);
            logger.addHandler(filehndl);
        catch(Exception e){
        logger.setLevel(Level.ALL);
        logger.setUseParentHandlers(false);
        logger.addHandler(hndl);
        logger.setLevel(Level.FINE);
        logger.info("LOGGING FACILITY IS READY !");
      private void processTask(QueueTask task){
        JumpProcessor proc = JumpProcessorGenerator.getProcessor(task);
        if(proc==null){
            logger.severe("Unknown task type: " + task.getType());
            return;
        proc.setJumpThread(myThread);
        proc.setLogger(logger);
        proc.setJumpRef(this);
        task.setProcStart(new java.util.Date());
        setExecution(task, true);
        new Thread(proc).start();
     private void processQueue(){
        //Endles loop for processing tasks from queue
        QueueTask task = null;
        while(true){
                try{
                    //null argument means: take first free, no matters which queue
                    do{
                        task = manager.getTask(activeQueues);
                        if(task!=null)
                            processTask(task);
                    while(task!=null);
                catch(Exception e){
                    logger.severe(e.getMessage());
            logger.fine("-------->Sleeping for " + idleSleep + " minutes...hzzzzzz (Active queues:"+ activeQueues.size()+")");
            try{
                if(!myThread.interrupted())
                    myThread.sleep(60*1000*idleSleep);
            catch(InterruptedException e){
                logger.fine("-------->Wakeing up !!!");
        }//while
    public void setMyThread(Thread t){
        myThread = t;
    /** This method is only used to start Jump as a separate thread this is
     *usefull to allow jump to access its own thread to sleep wait and synchronize
     *If you just start ProcessQueue from main method it is not possible to
     *use methods like Thread.sleep becouse object is not owner of current thread.
    public void run() {
        processQueue();
    /** This is just another facade to hide database access from another classes*/
    public void updateOraTaskStatus(QueueTask task, boolean success){
        try{
            manager.updateOraTaskStatus(task, success);
        catch(Exception e){
            logger.severe("Cannot update status of task table for task:" + task.getID() + "\nReason: " + e.getMessage());
    /** This is facade to JumpQueueManager method with same name to hide
     *existance of database and SQLExceptions from processor classes
     *Processor class calls this method to execute stored proc and it doesn't
     *take care about any SQL related issues including exceptions
    public void executeStoredProc(String proc) throws Exception{
        try{
            manager.executeStoredProc(proc);
        catch(Exception e){
            //logger.severe("Cannot execute stored procedure:"+ proc + "\nReason: " + e.getMessage());
            throw e;
     *This method is only to hide QueueManager object from access from JumpProcessors
     *It handles exceptions and datbase connecting/disconnecting and is called from
     *JumpProceesor thread.
    public void updateTaskStatus(int taskID, int status){
        try{
            manager.updateTaskStatus(taskID, status);
        catch(Exception e){
            logger.severe("Cannot update status of task: " + taskID + " to " + status + "\nReason: " + e.getMessage());
    public java.sql.Connection getDBConnection(){
        try{
            return manager.getNewConnection();
        catch(Exception e){
            logger.severe("Cannot acquire new database connection: " + e.getMessage());
            return null;
    protected synchronized void setExecution(QueueTask task, boolean active){
        if(active){
            activeQueues.put(new Integer(task.getQueueNum()), JumpConstants.TH_STAT_BUSY);
        else{
            activeQueues.remove(new Integer(task.getQueueNum()));
    public static void main(String[] args){
             try{
         System.out.println("The length-->"+args.length);
        System.out.println("It's " + new java.util.Date() + " now, have a good time.");
        if(args.length<5){
            System.out.println("More parameters needed:");
            System.out.println("1 - JDBC strign, 2 - DB User, 3 - DB Password, 4 - sleeping time (minutes), 5 - log file dir");
            return;
        Jump jump = new Jump(args[0], args[1], args[2], Integer.parseInt(args[3]), args[4]);
        Thread t1= new Thread(jump);
        jump.setMyThread(t1);
        t1.start();}
             catch(Exception e){
                  e.printStackTrace();
} The exception i am getting is
java.lang.NoClassDefFoundError: jdbc:oracle:thin:@localhost:1521:xe
Exception in thread "main" ERROR: JDWP Unable to get JNI 1.2 environment, jvm->GetEnv() return code = -2
JDWP exit error AGENT_ERROR_NO_JNI_ENV(183): [../../../src/share/back/util.c:820] Please help me.....
Thanks in advance.....sathya

I am not willing to wade through the code, but this portion makes me conjecture your using an Oracle connect string instead of a class name.
java.lang.NoClassDefFoundError: jdbc:oracle:thin:@localhost:1521:xe

Using a java program to fill in forms using information from a spreadsheet

I had an idea to "automate" some data entry at work and need to know if my idea is feasible with Java. Here is the back story:
I work on a research project and we have all of our contact data in an Excel spreadsheet (I know access may be better for this but for "political reasons" I just set it up in Excel). Every day we need to pay participants and this is done through a third party website. When the participant is new to this website we need to fill in all their personal information via a form on the webpage. Since we already have all their information stored in a spreadsheet, I was thinking we could create a little program that pulls the data from the excel sheet and inserts it into the form fields.
Can this be done with a simple java program?
Thank you for any help!

peroija wrote:
Can this be done with a simple java program?No.
Can this be done with a java program?Yes. You could certainly have your page upload the spreadsheet to your server, and you could certainly have your server program attempt to extract the data from Excel using Apache POI or JExcel or something like that. But you have to be prepared for people to upload the wrong file, or the right file in which the users have chosen unusual date formats, and so on. You could make things easier by distributing a spreadsheet which is locked down so that the users can only enter the information in specific places and specific formats, but it looks like you have missed that opportunity too.

Help--How can I open only one java program at one time?

How can I open only one java program(same program) in Windows at one time?

In Java 1.5, you can use the JVM's own monitoring APIs to examine what other JVMs are running on the system, and what applications they're running.
It's general and powerful, but complex. The socket/file/whatever approach is cleaner, and probably more suited to your usage.
Don't bother trying to use the Windows task manager for this sort of thing. You have to write messy native code, and it isn't reliable after all that anyway.

WLS JMS supports the clients developed by using non-java program languages,such as,c++,VB...

          WLS JMS supports the clients developed by using non-java program languages,such
          as,c++,VB?


The short answer is yes. This is a frequently asked question. I
          suggest searching this newsgroup in google using terms like "C++",
          "IIOP", ".NET", "JCOM".
          Note also that WL 8.1 (now out in beta) contains a thin java client
          (something like 0 or 300K without JMS, 700k with. The 0K client comes
          from leveraging WL's IIOP support.)
          Tom, BEA
          jerry8006 wrote:
          > WLS JMS supports the clients developed by using non-java program languages,such
          > as,c++,VB?

How to restart computer using simple java program

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