Swing uimanager affecting all java programs?

I set a ton of UIManager properties like:
UIManager.put("ScrollBar.thumb", java.awt.SystemColor.activeCaption);
However, when I do this, these become the defaults for all java programs until the virtual machine is reset. This is kind of screwy!!! I set these values in one applet and change the look and feel of the java console and other applets that will be run. How is this possible? I don't know if this is a "bug" or just a poor design.
Any thoughts?

Maybe you should try just a few questions at a time?

Similar Messages

QuickTime installation breaks all Java programs.

There is a bug in the QuickTime installation program for Windows that causes all Java programs to fail whenever QuickTime is installed or updated. As part of the installation, QuickTime updates the system environment variable CLASSPATH to reference a Java .jar file needed by QuickTine in order to run properly. This reference is C:\Program Files\Java\jre1.6.0_01\lib\ext\QTJava.zip.
The problem is that in Windows, any file path that contains whitespace characters must be enclosed in quotation marks. This is because on the command line, Windows interprets any whitespace character to be a parameter seperator. So when Windows tries to resolve the file path, it resolves to two seperate paths, "C:\Program" and "Files\Java\jre1.6.0_01\lib\ext\QTJava.zip". This causes all Java applications to generate the following error: java.lang.NoClassDefFoundError: Files\Java\jre1/6/0_01\lib\ext\QTJava/zip.
The solution to this problem has been well known for years, is widely published, and is very simple to implement. Enclose the file path in quotation marks, so that the CLASSPATH entry is exactly as follows (including quotation marks) "C:\Program Files\Java\jre1.6.0_01\lib\ext\QTJava.zip". This tells Windows that everything inside the quotation marks is a single parameter, which then lets all Java applications run properly. Everytime there is a new version of QuickTime I have to field numerous complaints from co-workers that they can no longer run our Java applications. This bug has existed for at least two major release versions, 6.x and 7.x.
Please fix this bug.
Windows XP Pro
Windows XP Pro

A jar file does not have to be an installation program. The jar file can be your entire program neatly encased into one file. If you mess around with the manifest file, the jar file can be executed by double clicking on it.
Example: You have a program that you execute from the command line using: java Program
First, write a text file that has:
Main-Class: Tagssave it as manifest.txt. Make sure to put a blank line at the end of the file. Then, on the command line, type:
jar cvfm Prog.jar manifest.txt *.class
Done! Double click on Prog.jar and let me know if that is what you were looking for.
Brad

When using safari, my screen will suddenly scroll all the way to the bottom and will not resound to any commands. This affects all running programs. How do I stop this?

When I am on the internet, my screen will suddenly scroll all the way to the bottom and will not respond to any commands. All of the other programs are then affected the same way and you cannot even use the commands at the top of the screen becayse they all scroll to the bottom. After a while, the screen resets by itself. Help.

It sounds like a problem wih the backlight inverter. Usually they just go, instead of on and off.
In a dark room hold a flashlight on the display when it blacks out. If you can see the items on the desktop, it's probably the backlight.

Can't Compile All Java Programs

I've installed java and have put the bin folder in the beginning of the environmental variables path value and separated the other path variables after it with a semicolon and no spaces. I then tried to run a hello world program (javac HelloApp.java) under the correct folder, but instead received a message ('javac' is not recognized as an internal or external command, operable program or batch file). Can anyone help me?

Install jdk
point your path to jdk's --> bin folder
create additional variable name--> classpath
point it to jdk's lib folder
.ok.
Restart
Now --> start -->run-->cmd--> javac [ enter ] if you get +ve output then 99% you have done it
now start -->run-->cmd--> java [ enter ] if you get this also then your done!!!!!!!!

Launch many java programs at runtime

Hi i got one question.
i have a list of java program ina file.
i read this file and get each program names.
i would like to launch all java programs at Runtime from my main Java application.
here is my code so far:
String fileName = expansion + ".txt";
          try
               File file = new File(fileName);
               FileReader     fileReader= new FileReader(file);
               BufferedReader bufferReader = new BufferedReader(fileReader);
               while((program=bufferReader.readLine())!= null)
                    Runtime launch=Runtime.getRuntime();
                    System.out.println("I launch "+ program);
                    launch.exec("cmd.exe /c start /c cd /bin");
                    launch.exec("java "+program);
this does not work. How can i handle this?
thank you
seb

while((program==bufferReader.readLine())
!= null) {Sorry, I meant
while((program==bufferReader.readLine())!= null) {{=^)

How to list all OS processes from a java program

I want to list/kill all OS processes from a java program, or a part from all processes according to a filter on a name of process.
a similar functionality is ps in Unix or taskkill in Windows XP.
Thanks!

Hi,
I was looking for such lib, but finally I decided to accomplish the job with my fingers end ;-). It maigh be helful for u guys:
// is written for x based OSs
private static void killProcess(Process process) {
if (process == null)
return;
process.destroy();
private static void closeProcessStreams(Process process) {
try {
process.getErrorStream().close();
} catch (IOException eyeOhEx) {
private static void listPHPs() {
Process proc = null;
Runtime rt = Runtime.getRuntime();
int exitVal = 0;
try {
proc = rt.exec(" ps -C php"); // here use ur filter. issue "man ps" in linux for more info
catch (Exception ex) {
System.out.println(ex.getMessage());
killProcess(proc);
return;
try {
// process the return list of ur command
InputStream stdReturnStr = proc.getInputStream();
InputStreamReader isr = new InputStreamReader(stdReturnStr);
BufferedReader br = new BufferedReader(isr);
String line = null;
String returnMsg = "";
boolean firstLine = true;
int[] allPIDs = new int[100]; // finally we have an array of PIDs
int PIDCount = 0;
while ( (line = br.readLine()) != null) {
if (!firstLine){ // the first line is title, ignore it
returnMsg += line + "\n";
String PID = line.trim().split(" ")[0];
System.out.println(PID);
try{
allPIDs[PIDCount] = Integer.parseInt(PID);
PIDCount++;
}catch(Exception ex){
else
firstLine = false;
System.out.println(returnMsg);
catch (Exception t) {
System.out.println(t.getMessage());
killProcess(proc);
return;
try {
exitVal = proc.waitFor();
catch (Exception t) {
System.out.println(t.getMessage());
killProcess(proc);
return;
closeProcessStreams(proc);
Thats it!

Exception at javax.swing.UIManager.setLookAndFeel(UIManager.java:435)

Only in one machine (AIX 5.2 with J2RE 1.3.1 IBM) I got the following exception:
"main" (TID:0x300C19D8, sys_thread_t:0x3003EF58, state:R, native ID:0x1) prio=5
     at java.security.AccessController.doPrivileged(Native Method)
     at sun.java2d.SunGraphicsEnvironment.<init>(SunGraphicsEnvironment.java:105)
     at sun.awt.X11GraphicsEnvironment.<init>(X11GraphicsEnvironment.java:82)
     at java.lang.Class.newInstance0(Native Method)
     at java.lang.Class.newInstance(Class.java:262)
     at java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment(GraphicsEnvironment.java:72)
     at java.awt.Font.initializeFont(Font.java:285)
     at java.awt.Font.<init>(Font.java:319)
     at javax.swing.plaf.FontUIResource.<init>(FontUIResource.java:51)
     at javax.swing.plaf.basic.BasicLookAndFeel.getFont(BasicLookAndFeel.java:252)
     at javax.swing.plaf.basic.BasicLookAndFeel.initComponentDefaults(BasicLookAndFeel.java:271)
     at javax.swing.plaf.metal.MetalLookAndFeel.initComponentDefaults(MetalLookAndFeel.java:210)
     at javax.swing.plaf.basic.BasicLookAndFeel.getDefaults(BasicLookAndFeel.java:80)
     at javax.swing.plaf.metal.MetalLookAndFeel.getDefaults(MetalLookAndFeel.java:1088)
     at javax.swing.UIManager.setLookAndFeel(UIManager.java:408)
     at javax.swing.UIManager.setLookAndFeel(UIManager.java:435)
Other machine works fine.
Any suggestion?
Grazie

So I can only assume that I have the the necessary resources installed correctly. Any thoughts on what might be causing my problem?
com.sun.java.plat.windows.WindowsClassicLookAndFeel // the class you're trying to set
com.sun.java.plaf.windows.WindowsClassicLookAndFeel // the class that is actually availableSee the difference?
~

High CPU usage while running a java program

Hi All,
Need some input regarding one issue I am facing.
I have written a simple JAVA program that lists down all the files and directories under one root directory and then copies/replicates them to another location. I am using java.nio package for copying the files. When I am running the program, everything is working fine. But the process is eating up all the memories and the CPU usage is reaching upto 95-100%. So the whole system is getting slowed down.
Is there any way I can control the CPU usage? I want this program to run silently without affecting the system or its performance.

Hi,
Below is the code snippets I am using,
For listing down files/directories:
        static void Process(File aFile, File aFile2) {
          spc_count++;
          String spcs = "";
          for (int i = 0; i < spc_count; i++)
          spcs += "-";
          if(aFile.isFile()) {
               System.out.println(spcs + "[FILE] " + aFile2.toURI().relativize(aFile.toURI()).getPath());
               String newFile = dest + aFile2.toURI().relativize(aFile.toURI()).getPath();
               File nf = new File(newFile);
               try {
                    FileCopy.copyFile(aFile ,nf);
               } catch (IOException ex) {
                    Logger.getLogger(ContentList.class.getName()).log(Level.SEVERE, null, ex);
          } else if (aFile.isDirectory()) {
               //System.out.println(spcs + "[DIR] " + aFile2.toURI().relativize(aFile.toURI()).getPath());
               String newDir = dest + aFile2.toURI().relativize(aFile.toURI()).getPath();
               File nd = new File(newDir);
               nd.mkdir();
               File[] listOfFiles = aFile.listFiles();
               if(listOfFiles!=null) {
                    for (int i = 0; i < listOfFiles.length; i++)
                         Process(listOfFiles, aFile2);
               } else {
                    System.out.println(spcs + " [ACCESS DENIED]");
          spc_count--;
for copying files/directories:public static void copyFile(File in, File out)
throws IOException {
FileChannel inChannel = new
FileInputStream(in).getChannel();
FileChannel outChannel = new
FileOutputStream(out).getChannel();
try {
inChannel.transferTo(0, inChannel.size(),
outChannel);
catch (IOException e) {
throw e;
finally {
if (inChannel != null) inChannel.close();
if (outChannel != null) outChannel.close();
Please let me know if any better approach is there. But as I already said, currently it's eating up the whole memory.
Thanks in advance.

Need help in creating a java program

Hi everyone.
I'd like to say before i start about my problem, that i've only begun learning java and my teacher hasn't explained anything at all. He only showed us by doing it himself and then showing us the final version. I've searched a little on how to program but i get little success in finding a good tutorial.
I need help creating a program which has been assigned to me due in a few days in which i can't contact my teacher for help.
I need to write a java program which inputs 3 items. The number of kilometres you drove, the number of litres of gas you used and the price you paid for the gas. Then, the program must calculate the number of litres used per 100km driven, which is litres divided by kilometres times 100, how much it costs to drive 100km, which is the result (a) times the price per litre and the number of miles per American gallon of gas ( one American gallon = 3.785 litres, and one mile = 1.609 km.
The program has to output my name, the inputs given, the results computed and a message saying "Program Complete".
To give you what i've done to begin with, from what i understood, is:
import javax.swing.JOptionPane;
public class prog1
     public static void main(String args[])
          final double americanGallon = 3.785;
          final double mile = 1.609;
          kilometresDriven,
          gasUsed;
          priceOfLiterGas;
          System.out.println("My Name");
          System.out.println("Number of kilometres driven:");
          kilometresDriven = JOptionPane.showInputDialog ("Kilometres Driven");
          System.out.println("Number of Litres of gas used:");
          gasUsed = JOptionPane.showInputDialog ("Litres of gas used");
          System.out.println("Price of a liter of gas:");
          priceOfLiterGas = JoptionPane.showInputDialog("Price per liter");
Up to now, that's all i've got. i know i'm wrong, but i'm not sure how to do this. Could someone give me an outline of what this program is suppose to look like?
Thanks in advance.

Here's an update on my program. I've worked on certain details and would need your comments whether it contains errors. I'd also want to know if it would work or not because i don't know how to check it on my computer.
Here's the update:
import javax.swing.JOptionPane;
public class Prog1
public static void main(String args[])
String name;
double kmDriven;
double litresUsed;
double pricePaidForGas;
double priceOfALiter;
name = JOptionPane.showInputDialog("Name");
input = JOptionPane.showInputDialog("Number of km driven");
kmDriven = Double.parseDouble (input);
input = JOptionPane.showInputDialog("Number of litres of gas used");
litresUsed = Double.parseDouble (input);
input = JOptionPane.showInputDialog("Price paid for gas");
pricePaidForGas = Double.parseDouble (input);
input = JOptionPane.showInputDialog("Price of a litre of gas");
priceOfALiter = Double.parseDouble (input);
a = (litresUsed/kmDriven)*100;
b = ((litresUsed/kmDriven)*100)*priceOfALiter);
c = (kmDriven/1.609)
System.out.println("Name:" + name);
System.out.println("Number of litres used per 100km:" + a);
System.out.println("Cost of driving 100km" + b);
System.out.println("Number of miles per American Gallon of Gas:" + c);
System.out.println("Program Complete");
System.exit(0);
Comments please.
Thanks in advance

Using the Insert statement in a Java program without hardcoding the data

hello.
this is james mcfadden. i have developed a program called Demo.java, which is used with another program called QueryTableModel.java (a program that allows data to be viewed in a JTable). The Demo.java program displays a menu, connects to a database, allows the user to add data into the database and allows the user to view data that is already in the database. I have a problem with the Demo.java program. I have hardcoded the Insert statement in it. How do you use the Insert statement to put data into a database without hardcoding the data?
import java.awt.*;//Contains all of the classes for creating user interfaces and for painting graphics and images
import java.awt.event.*;//Provides interfaces and classes for dealing with different types of events fired by AWT components
import javax.swing.*;//Provides a set of lightweight components that, to the maximum degree possible, work the same on all platforms
import javax.swing.table.*;//Provides classes and interfaces for dealing with javax.swing.JTable
import javax.swing.JOptionPane;//provides a class that makes it easy to pop up a standard dialog box that prompts users for a value or informs them of something
import java.sql.*;//Provides the API for accessing and processing data stored in a data source using the Java programming language
public class Demo extends JFrame{
   static String url = "jdbc:odbc:VideoLibrary";//a static variable that allows a connection to be made to a database called VideoLibrary
   static Statement stmt;//a static variable that allows a statement to be made once a connection is set up
   static Connection con;//a static interface that allows a connection to be made to a database
     //global variables
     JTextField hostField;//a class that allows a line of text to be changed
   JTextField queryField;//a class that allows a line of text to be changed
   QueryTableModel qtm;//a class that shows and changes regular two-dimensional tables of cells
   JComboBox comboBox;//a class that puts a button or editable field and a drop-down list together
   public static void main(String args[]){
      int choice=-1;//a variable of type int that is set to -1
          do{
         choice=getChoice();//invokes the method getChoice()
         if(choice!=0){
            getSelected(choice);//invokes the method getSelected(choice)
         }//end if
               //if the user chooses 5, it will cause him or her to exit the system
      }while(choice!=5);//end do-while
      System.exit(0);//closes down the menu screen
   }//end main
   public static int getChoice(){
      String choice;//a variable of type string
      int ch;//a variable of type int
      choice = JOptionPane.showInputDialog(null,"1. Maintain product details\n"+"2. Maintain member details\n"+"3. Maintain rental details\n"+"4. View product, member and rental details\n"+"5. Log Off\n\n"+"Enter your choice");//asks the user for some input
          ch = Integer.parseInt(choice);//a class that wraps a value of the primitive type int in an object
          return ch;//a method that returns an integer value
   }//end getChoice
   public static void getSelected(int choice){
          if(choice==1){
         maintainProductDetails();//invokes the method maintainProductDetails()
      }//end if
      if(choice==2){
         maintainMemberDetails();//invokes the method maintainMemberDetails()
      }//end if
          if(choice==3){
         maintainRentalDetails();//invokes the method maintainRentalDetails()
      }//end if
          if(choice==4){
             Demo test = new Demo();//invokes the constructor Demo()
         test.setVisible(true);//shows the JTable component by marking it as visible
          }//end if
   }//end getSelected
   public static Connection getConnection(){
      try {
         Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");//used to create a JDBC connection using a database
      }//end try
          catch(java.lang.ClassNotFoundException e){//causes an exception to be thrown when an application tries to load in a class through its string name
         System.err.print("ClassNotFoundException: ");//displays an error message
         System.err.println(e.getMessage());//returns the exception that was raised if an error occurred while attempting to load the ClassNotFoundException class
      }//end catch
      try {
         con=DriverManager.getConnection(url,"","");//tries to create a connection with the database using the DriverManager class
      }//end try
          catch(SQLException ex) {
         System.err.println("SQLException: " + ex.getMessage());//returns an SQL error message
      }//end catch
      return con;
   }//end getConnection
   public static void maintainProductDetails(){
      Connection con = getConnection();//creates a connection with the database
      String addProduct1, addProduct2, addProduct3, addProduct4, addProduct5, addProduct6, addProduct7, addProduct8, addProduct9, addProduct10;//string variables that represent information about the different types of product data that will be stored in the database
      addProduct1 = "insert into Product values (110001, 'The Killers - Sams Town', 5.00, 'G', 'CD', 2006)";
      addProduct2 = "insert into Product values (110002, 'Robbie Williams - Rudebox', 5.00, 'G', 'CD', 2006)";
      addProduct3 = "insert into Product values (110003, 'Razorlight - Razorlight', 5.00, 'G', 'CD', 2006)";
      addProduct4 = "insert into Product values (110004, 'My Chemical Romance - The Black Parade', 5.00, 'G', 'CD', 2006)";
      addProduct5 = "insert into Product values (110005, 'Snow Patrol - Eyes Open', 5.00, 'G', 'CD', 2006)";
      addProduct6 = "insert into Product values (110006, 'Scissor Sisters - Ta-Dah!', 5.00, 'G', 'CD', 2006)";
          addProduct7 = "insert into Product values (110007, 'Lovesounds - Justin Timberlake', 5.00, 'G', 'CD', 2006)";
      addProduct8 = "insert into Product values (110008, 'Director - We thrive on big cities', 5.00, 'G', 'CD', 2006)";
      addProduct9 = "insert into Product values (110009, 'Roxette - Roxette hits', 5.00, 'G', 'CD', 2006)";
      addProduct10 = "insert into Product values (110010, 'Pussy Cat Dolls - PCD', 5.00, 'G', 'CD', 2006)";
          try {
         stmt = con.createStatement();//Creates a Statement object for sending SQL statements to the database
             //statements are allowed to be made once a connection is set up
             stmt.executeUpdate(addProduct1);
         stmt.executeUpdate(addProduct2);
         stmt.executeUpdate(addProduct3);
         stmt.executeUpdate(addProduct4);
               stmt.executeUpdate(addProduct5);
         stmt.executeUpdate(addProduct6);
             stmt.executeUpdate(addProduct7);
         stmt.executeUpdate(addProduct8);
         stmt.executeUpdate(addProduct9);
         stmt.executeUpdate(addProduct10);
         stmt.close();//closes the Statement object
         con.close();//terminates the connection with the database
      }//end try
          catch(SQLException ex) {
         System.err.println("SQLException: " + ex.getMessage());//returns an SQL error message
      }//end catch
   }//end maintainProductDetails
   public static void maintainMemberDetails(){
      Connection con = getConnection();//creates a connection with the database
      String addMember1, addMember2, addMember3, addMember4, addMember5, addMember6, addMember7, addMember8, addMember9, addMember10;//string variables that represent information about the member data that will be stored in the database
      addMember1 = "insert into Member values (1234, 'Ann', 'Smyth', 'Upper Killult, Falcarragh, Co. Donegal', '(074)-9135210', '(087)-2030172', #5/11/85#, #5/12/06#)";
      addMember2 = "insert into Member values (2345, 'John', 'Murphy', 'Lower Killult, Falcarragh, Co. Donegal', '(074)-9135211', '(087)-2030173', #4/12/85#, #6/13/06#)";
      addMember3 = "insert into Member values (1324, 'James', 'McFadden', 'Lower Ardsbeg, Gortahork, Co. Donegal', '(074)-9165314', '(087)-2030171', #4/11/85#, #6/14/06#)";
      addMember4 = "insert into Member values (1235, 'Frankie', 'Ferry', 'Ardsmore, Gortahork, Co. Donegal', '(074)-9165325', '(087)-2031234', #6/13/60#, #6/15/06#)";
      addMember5 = "insert into Member values (1236, 'Daniel', 'McKimm', 'Ballyness, Falcarragh, Co. Donegal', '(074)-9135212', '(087)-2030184', #5/14/73#, #6/16/06#)";
      addMember6 = "insert into Member values (2346, 'Stephen', 'Doohan', 'Ballyness, Falcarragh, Co. Donegal', '(074)-9135213', '(087)-2030185', #6/13/85#, #5/13/06#)";
      addMember7 = "insert into Member values (2347, 'James', 'Ferry', 'Meenlaragh, Gortahork, Co.Donegal', '(074)-9165360', '(087)-2031345', #9/12/85#, #5/14/06#)";
      addMember8 = "insert into Member values (2348, 'Liam', 'Cannon', 'Derryconner, Gortahork, Co.Donegal', '(074)-9165324', '(087)-2031456', #4/11/86#, #5/15/06#)";
      addMember9 = "insert into Member values (2401, 'Ciaran', 'Ferry', 'Brinalack, Gweedore, Co.Donegal', '(074)-9176425', '(087)-2030282', #9/12/85#, #5/16/06#)";
      addMember10 = "insert into Member values (2402, 'Ciaran', 'McGee', 'Derrybeg, Gweedore, Co.Donegal', '(074)-9176536', '(087)-2030393', #9/14/85#, #5/18/06#)";
      try{
         stmt = con.createStatement();//Creates a Statement object for sending SQL statements to the database
               //statements are allowed to be made once a connection is set up
               stmt.executeUpdate(addMember1);
         stmt.executeUpdate(addMember2);
         stmt.executeUpdate(addMember3);
               stmt.executeUpdate(addMember4);
               stmt.executeUpdate(addMember5);
               stmt.executeUpdate(addMember6);
               stmt.executeUpdate(addMember7);
               stmt.executeUpdate(addMember8);
               stmt.executeUpdate(addMember9);
               stmt.executeUpdate(addMember10);
         stmt.close();//closes the Statement object
         con.close();//terminates the connection with the database
      }//end try
          catch(SQLException ex) {
         System.err.println("SQLException: " + ex.getMessage());//returns an SQL error message
      }//end catch
   }//end maintainMemberDetails
     public static void maintainRentalDetails(){
      Connection con = getConnection();//creates a connection with the database
      String addRental1, addRental2, addRental3, addRental4, addRental5, addRental6, addRental7, addRental8, addRental9, addRental10;//string variables that represent information about the loan data that will be stored in the database
      addRental1 = "insert into Rental values (110001, 'The Killers - Sams Town', 1234, 'Ann', 'Smyth', #9/01/06#, #9/10/06#, 'Yes', 2.00)";
      addRental2 = "insert into Rental values (120001, 'Mission Impossible 3', 2345, 'John', 'Murphy', #9/02/06#, #9/09/06#, 'No', 0.00)";
      addRental3 = "insert into Rental values (130001, 'Need for Special Carbon', 1324, 'James', 'McFadden', #9/03/06#, #9/12/06#, 'Yes', 2.00)";
      addRental4 = "insert into Rental values (110002, 'Robbie Williams - Rudebox', 1235, 'Frankie', 'Ferry', #9/04/06#, #9/11/06#, 'No', 0.00)";
      addRental5 = "insert into Rental values (120015, 'Prime', 1236, 'Daniel', 'McKimm', #9/05/06#, #9/14/06#, 'Yes', 2.00)";
      addRental6 = "insert into Rental values (130015, 'FIFA 07', 2346, 'Stephen', 'Doohan', #9/06/06#, #9/13/06#, 'No', 0.00)";
      addRental7 = "insert into Rental values (110009, 'Roxette - Roxette hits', 2347, 'James', 'Ferry', #9/07/06#, #9/16/06#, 'Yes', 2.00)";
      addRental8 = "insert into Rental values (120003, 'The Break Up', 2348, 'Liam', 'Cannon', #9/08/06#, #9/15/06#, 'No', 0.00)";
      addRental9 = "insert into Rental values (130027, 'Gears of War', 2401, 'Ciaran', 'Ferry', #9/09/06#, #9/18/06#, 'Yes', 2.00)";
      addRental10 = "insert into Rental values (110021, 'Scooter - Mind the Gap', 2402, 'Ciaran', 'McGee', #9/10/06#, #9/17/06#, 'No', 0.00)";
      try{
         stmt = con.createStatement();//Creates a Statement object for sending SQL statements to the database
               //statements are allowed to be made once a connection is set up
               stmt.executeUpdate(addRental1);
         stmt.executeUpdate(addRental2);
         stmt.executeUpdate(addRental3);
               stmt.executeUpdate(addRental4);
               stmt.executeUpdate(addRental5);
               stmt.executeUpdate(addRental6);
               stmt.executeUpdate(addRental7);
               stmt.executeUpdate(addRental8);
               stmt.executeUpdate(addRental9);
               stmt.executeUpdate(addRental10);
         stmt.close();//closes the Statement object
         con.close();//terminates the connection with the database
      }//end try
          catch(SQLException ex) {
         System.err.println("SQLException: " + ex.getMessage());//returns an SQL error message
      }//end catch
   }//end maintainRentalDetails
   public Demo(){//a constructor
      super("Demo Test Frame");//overrides the constructor
      setSize(350, 200);//Resizes this component so that it has width of 350 and height of 200
      comboBox = new JComboBox();//invokes the class JComboBox
      comboBox.addItem("jdbc:odbc:VideoLibrary");//adds the specified item to the end of the scrolling list
      qtm = new QueryTableModel();//invokes the class QueryTableModel
      JTable table = new JTable(qtm);//a class that shows and changes regular two-dimensional tables of cells
      JScrollPane scrollpane = new JScrollPane(table);//a class that provides a scrollable view of a lightweight component
      JPanel p1 = new JPanel();//a class that puts the combo box and query field in a panel
      p1.setLayout(new GridLayout(3, 2));//Sets the layout manager for this container
      p1.add(comboBox);//Appends the specified component to the end of this container
      p1.add(new JLabel("Enter your query: "));//Appends the specified component to the end of this container
      p1.add(queryField = new JTextField());//Appends the specified component to the end of this container
      p1.add(new JLabel("Click here to send: "));//Appends the specified component to the end of this container
      JButton jb = new JButton("Search");//a class that is an implementation of a "push" button
      jb.addActionListener(new ActionListener(){//Adds an ActionListener to the button
         public void actionPerformed(ActionEvent e){
            qtm.setHostURL();//invokes the method setHostURL
            qtm.setQuery(queryField.getText().trim());//invokes the method setQuery; and returns the text that is presented by this text component and returns a copy of the string, with leading and trailing whitespaces omitted
      } );//end addActionListener
      p1.add(jb);//Appends the specified component to the end of this container
      getContentPane().add(p1, BorderLayout.NORTH);//Returns the content pane
      getContentPane().add(scrollpane, BorderLayout.CENTER);//Returns the content pane
   }//end Demo
}//end class Demo
import java.sql.*;//Provides the API for accessing and processing data stored in a data source using the Java programming language
import java.io.*;//Provides for system input and output through data streams, serialization and the file system
import java.util.Vector;//provides a class that implements a growable array of objects
import javax.swing.*;//Provides a set of lightweight components that, to the maximum degree possible, work the same on all platforms
import javax.swing.table.*;//Provides classes and interfaces for dealing with javax.swing.JTable
public class QueryTableModel extends AbstractTableModel{
     Vector cache;//a class that constructs an empty vector so that its internal data array has size 10 and its standard capacity increment is zero
     int colCount;//a variable that counts the number of columns in the three tables
     String[] headers;//a class that represents character strings and all string literals in this program are implemented as instances of the String class
     Connection db;//an interface that allows a connection to be made to a database
     Statement statement;//an interface that allows executes the given SQL statement, which returns a single ResultSet object
     String currentURL;//a variable that allows the URL to be displayed in a combo box
     public QueryTableModel(){//a constructor
          cache=new Vector();//constructs an empty vector so that its internal data array has size 10 and its standard capacity increment is zero
          try{
         Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");//used by opening a JDBC connection using an URL
          }//end try
          catch(Exception e){
               System.out.println("problem loading the driver ");//an error message
          }//end catch
     }//end QueryTableModel
     public String getColumnName(int i){//Returns the designated column's name
        return headers;//returns the name of each column in the three table
     }//end getColumnName
     public int getColumnCount(){//Returns the number of columns in the column model
     return colCount;//returns the number of columns in the three tables
     }//end getColumnCount
     public int getRowCount(){//Returns the number of rows in this table's model
     return cache.size();//returns the number of components in the vector
     }//end getRowCount
     public Object getValueAt(int row, int col){//Returns the cell value at row and column
          return ((String[])cache.elementAt(row))[col];//Returns the component at the specified index
     }//end getValueAt
     public void setHostURL(){//sets the URL for the database
     String url = "jdbc:odbc:VideoLibrary";//a variable that allows a connection to be made to a database called VideoLibrary
     closeDB();//invokes the method closeDB()
          try{
db=DriverManager.getConnection(url,"","");//tries to create a connection with the database using the DriverManager class
statement=db.createStatement();//Creates a Statement object for sending SQL statements to the database
}//end try
catch(Exception e){
System.out.println("Could not initialize the database.");//an error message
e.printStackTrace();//a Throwable method that prints this throwable and it's backtrace to the standard error stream
}//end catch
     }//end setHostURL
public void setQuery(String q){//sets the kind of query that is to be sent to the database
          cache=new Vector();//constructs an empty vector so that its internal data array has size 10 and its standard capacity increment is zero
String s="select * from Product";//a variable that causes all the data that is in the product table to be displayed in a JTable, which also means that all the data that is in both the member and rental tables can also be displayed in a JTable
          try{
               ResultSet rs=statement.executeQuery(q);//an interface that is used to generate a database result set by executing a statement that queries the database
               ResultSetMetaData meta=rs.getMetaData();//an interface that is used to get information about the types and properties of the columns in a ResultSet object
               colCount=meta.getColumnCount();//Returns the number of columns in this ResultSet object
               headers=new String[colCount];//gets the name of each column in the three tables
               for(int h=1;h<=colCount;h++){
                    headers[h-1]=meta.getColumnName(h);//Get the designated column's name
               }//end for
               while(rs.next()){
                    String[] record=new String[colCount];//stores the name of each column in the three tables in memory
                    for(int i=0;i<colCount;i++){
                         record[i]=rs.getString(i+1);//Retrieves the value of the designated column in the current row of this ResultSet object as a String
                    }//end for
                    cache.addElement(record);//Adds the specified component to the end of this vector, increasing its size by one
               }//end while
               fireTableChanged(null);//Forwards the given notification event to all TableModelListeners that registered themselves as listeners for this table model
          }//end try
          catch(Exception e){
               cache=new Vector();//constructs an empty vector so that its internal data array has size 10 and its standard capacity increment is zero
               e.printStackTrace();//a Throwable method that prints this throwable and it's backtrace to the standard error stream
          }//end catch
     }//end setQuery
     public void initDB(String url){
          try{
               db=DriverManager.getConnection(url);//tries to create a connection with the database using the DriverManager class
               statement=db.createStatement();//Creates a Statement object for sending SQL statements to the database
          }//end try
          catch(Exception e){
               System.out.println("Could not initialize the database.");//an error message
               e.printStackTrace();//a Throwable method that prints this throwable and it's backtrace to the standard error stream
          }//end catch
     }//end initDB
     public void closeDB(){
          try{
               if(statement!=null){
               statement.close();//Releases this Statement object's database and JDBC resources immediately instead of waiting for this to happen when it is automatically closed
               }//end if
               if(db!=null){
               db.close();//Releases this Connection object's database and JDBC resources immediately instead of waiting for them to be automatically released
               }//end if
          }//end try
          catch(Exception e){
               System.out.println("Could not close the current connection.");//an error message
               e.printStackTrace();//a Throwable method that prints this throwable and it's backtrace to the standard error stream
          }//end catch
     }//end closeDB
}//end class QueryTableModel

here's an uncommented version of the code.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.*;
import javax.swing.JOptionPane;
import java.sql.*;
public class Demo extends JFrame{
   static String url = "jdbc:odbc:VideoLibrary";
   static Statement stmt;
   static Connection con;
   JTextField hostField;
   JTextField queryField;
   QueryTableModel qtm;
   JComboBox comboBox;
   public static void main(String args[]){
      int choice=-1;
      do{
         choice=getChoice();
         if(choice!=0){
            getSelected(choice);
      }while(choice!=5);
      System.exit(0);
   public static int getChoice(){
      String choice;
      int ch;
      choice = JOptionPane.showInputDialog(null,"1. Maintain product details\n"+"2. Maintain member details\n"+"3. Maintain rental details\n"+"4. View product, member and rental details\n"+"5. Log Off\n\n"+"Enter your choice");
      ch = Integer.parseInt(choice);
      return ch;
   public static void getSelected(int choice){
      if(choice==1){
         maintainProductDetails();
      if(choice==2){
         maintainMemberDetails();
      if(choice==3){
         maintainRentalDetails();
      if(choice==4){
         Demo test = new Demo();
         test.setVisible(true);
   public static Connection getConnection(){
      try {
         Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
      catch(java.lang.ClassNotFoundException e){
         System.err.print("ClassNotFoundException: ");
         System.err.println(e.getMessage());
      try {
         con=DriverManager.getConnection(url,"","");
      catch(SQLException ex) {
         System.err.println("SQLException: " + ex.getMessage());
      return con;
   public static void maintainProductDetails(){
      Connection con = getConnection();
      String addProduct1, addProduct2, addProduct3, addProduct4, addProduct5, addProduct6, addProduct7, addProduct8, addProduct9, addProduct10;
      addProduct1 = "insert into Product values (110001, 'The Killers - Sams Town', 5.00, 'G', 'CD', 2006)";
      addProduct2 = "insert into Product values (110002, 'Robbie Williams - Rudebox', 5.00, 'G', 'CD', 2006)";
      addProduct3 = "insert into Product values (110003, 'Razorlight - Razorlight', 5.00, 'G', 'CD', 2006)";
      addProduct4 = "insert into Product values (110004, 'My Chemical Romance - The Black Parade', 5.00, 'G', 'CD', 2006)";
      addProduct5 = "insert into Product values (110005, 'Snow Patrol - Eyes Open', 5.00, 'G', 'CD', 2006)";
      addProduct6 = "insert into Product values (110006, 'Scissor Sisters - Ta-Dah!', 5.00, 'G', 'CD', 2006)";
      addProduct7 = "insert into Product values (110007, 'Lovesounds - Justin Timberlake', 5.00, 'G', 'CD', 2006)";
      addProduct8 = "insert into Product values (110008, 'Director - We thrive on big cities', 5.00, 'G', 'CD', 2006)";
      addProduct9 = "insert into Product values (110009, 'Roxette - Roxette hits', 5.00, 'G', 'CD', 2006)";
      addProduct10 = "insert into Product values (110010, '***** Cat Dolls - PCD', 5.00, 'G', 'CD', 2006)";
      try {
         stmt = con.createStatement();
         stmt.executeUpdate(addProduct1);
         stmt.executeUpdate(addProduct2);
         stmt.executeUpdate(addProduct3);
         stmt.executeUpdate(addProduct4);
         stmt.executeUpdate(addProduct5);
         stmt.executeUpdate(addProduct6);
         stmt.executeUpdate(addProduct7);
         stmt.executeUpdate(addProduct8);
         stmt.executeUpdate(addProduct9);
         stmt.executeUpdate(addProduct10);
         stmt.close();
         con.close();
      catch(SQLException ex) {
         System.err.println("SQLException: " + ex.getMessage());
   public static void maintainMemberDetails(){
      Connection con = getConnection();
      String addMember1, addMember2, addMember3, addMember4, addMember5, addMember6, addMember7, addMember8, addMember9, addMember10;
      addMember1 = "insert into Member values (1234, 'Ann', 'Smyth', 'Upper Killult, Falcarragh, Co. Donegal', '(074)-9135210', '(087)-2030172', #5/11/85#, #5/12/06#)";
      addMember2 = "insert into Member values (2345, 'John', 'Murphy', 'Lower Killult, Falcarragh, Co. Donegal', '(074)-9135211', '(087)-2030173', #4/12/85#, #6/13/06#)";
      addMember3 = "insert into Member values (1324, 'James', 'McFadden', 'Lower Ardsbeg, Gortahork, Co. Donegal', '(074)-9165314', '(087)-2030171', #4/11/85#, #6/14/06#)";
      addMember4 = "insert into Member values (1235, 'Frankie', 'Ferry', 'Ardsmore, Gortahork, Co. Donegal', '(074)-9165325', '(087)-2031234', #6/13/60#, #6/15/06#)";
      addMember5 = "insert into Member values (1236, 'Daniel', 'McKimm', 'Ballyness, Falcarragh, Co. Donegal', '(074)-9135212', '(087)-2030184', #5/14/73#, #6/16/06#)";
      addMember6 = "insert into Member values (2346, 'Stephen', 'Doohan', 'Ballyness, Falcarragh, Co. Donegal', '(074)-9135213', '(087)-2030185', #6/13/85#, #5/13/06#)";
      addMember7 = "insert into Member values (2347, 'James', 'Ferry', 'Meenlaragh, Gortahork, Co.Donegal', '(074)-9165360', '(087)-2031345', #9/12/85#, #5/14/06#)";
      addMember8 = "insert into Member values (2348, 'Liam', 'Cannon', 'Derryconner, Gortahork, Co.Donegal', '(074)-9165324', '(087)-2031456', #4/11/86#, #5/15/06#)";
      addMember9 = "insert into Member values (2401, 'Ciaran', 'Ferry', 'Brinalack, Gweedore, Co.Donegal', '(074)-9176425', '(087)-2030282', #9/12/85#, #5/16/06#)";
      addMember10 = "insert into Member values (2402, 'Ciaran', 'McGee', 'Derrybeg, Gweedore, Co.Donegal', '(074)-9176536', '(087)-2030393', #9/14/85#, #5/18/06#)";
      try{
         stmt = con.createStatement();
         stmt.executeUpdate(addMember1);
         stmt.executeUpdate(addMember2);
         stmt.executeUpdate(addMember3);
         stmt.executeUpdate(addMember4);
         stmt.executeUpdate(addMember5);
         stmt.executeUpdate(addMember6);
         stmt.executeUpdate(addMember7);
         stmt.executeUpdate(addMember8);
         stmt.executeUpdate(addMember9);
         stmt.executeUpdate(addMember10);
         stmt.close();
         con.close();
      catch(SQLException ex) {
         System.err.println("SQLException: " + ex.getMessage());
   public static void maintainRentalDetails(){
      Connection con = getConnection();
      String addRental1, addRental2, addRental3, addRental4, addRental5, addRental6, addRental7, addRental8, addRental9, addRental10;
      addRental1 = "insert into Rental values (110001, 'The Killers - Sams Town', 1234, 'Ann', 'Smyth', #9/01/06#, #9/10/06#, 'Yes', 2.00)";
      addRental2 = "insert into Rental values (120001, 'Mission Impossible 3', 2345, 'John', 'Murphy', #9/02/06#, #9/09/06#, 'No', 0.00)";
      addRental3 = "insert into Rental values (130001, 'Need for Special Carbon', 1324, 'James', 'McFadden', #9/03/06#, #9/12/06#, 'Yes', 2.00)";
      addRental4 = "insert into Rental values (110002, 'Robbie Williams - Rudebox', 1235, 'Frankie', 'Ferry', #9/04/06#, #9/11/06#, 'No', 0.00)";
      addRental5 = "insert into Rental values (120015, 'Prime', 1236, 'Daniel', 'McKimm', #9/05/06#, #9/14/06#, 'Yes', 2.00)";
      addRental6 = "insert into Rental values (130015, 'FIFA 07', 2346, 'Stephen', 'Doohan', #9/06/06#, #9/13/06#, 'No', 0.00)";
      addRental7 = "insert into Rental values (110009, 'Roxette - Roxette hits', 2347, 'James', 'Ferry', #9/07/06#, #9/16/06#, 'Yes', 2.00)";
      addRental8 = "insert into Rental values (120003, 'The Break Up', 2348, 'Liam', 'Cannon', #9/08/06#, #9/15/06#, 'No', 0.00)";
      addRental9 = "insert into Rental values (130027, 'Gears of War', 2401, 'Ciaran', 'Ferry', #9/09/06#, #9/18/06#, 'Yes', 2.00)";
      addRental10 = "insert into Rental values (110021, 'Scooter - Mind the Gap', 2402, 'Ciaran', 'McGee', #9/10/06#, #9/17/06#, 'No', 0.00)";
      try{
         stmt = con.createStatement();
         stmt.executeUpdate(addRental1);
         stmt.executeUpdate(addRental2);
         stmt.executeUpdate(addRental3);
         stmt.executeUpdate(addRental4);
         stmt.executeUpdate(addRental5);
         stmt.executeUpdate(addRental6);
         stmt.executeUpdate(addRental7);
         stmt.executeUpdate(addRental8);
         stmt.executeUpdate(addRental9);
         stmt.executeUpdate(addRental10);
         stmt.close();
         con.close();
      catch(SQLException ex) {
         System.err.println("SQLException: " + ex.getMessage());
   public Demo(){
      super("Demo Test Frame");
      setSize(350, 200);
      comboBox = new JComboBox();
      comboBox.addItem("jdbc:odbc:VideoLibrary");
      qtm = new QueryTableModel();
      JTable table = new JTable(qtm);
      JScrollPane scrollpane = new JScrollPane(table);
      JPanel p1 = new JPanel();
      p1.setLayout(new GridLayout(3, 2));
      p1.add(comboBox);
      p1.add(new JLabel("Enter your query: "));
      p1.add(queryField = new JTextField());
      p1.add(new JLabel("Click here to send: "));
      JButton jb = new JButton("Search");
      jb.addActionListener(new ActionListener(){
         public void actionPerformed(ActionEvent e){
            qtm.setHostURL();
            qtm.setQuery(queryField.getText().trim());
      p1.add(jb);
      getContentPane().add(p1, BorderLayout.NORTH);
      getContentPane().add(scrollpane, BorderLayout.CENTER);
import java.sql.*;
import java.io.*;
import java.util.Vector;
import javax.swing.*;
import javax.swing.table.*;
public class QueryTableModel extends AbstractTableModel{
     Vector cache;
     int colCount;
     String[] headers;
     Connection db;
     Statement statement;
     String currentURL;
     public QueryTableModel(){
          cache=new Vector();
          try{
         Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
          catch(Exception e){
               System.out.println("problem loading the driver ");
     public String getColumnName(int i){
        return headers;
     public int getColumnCount(){
     return colCount;
     public int getRowCount(){
     return cache.size();
     public Object getValueAt(int row, int col){
          return ((String[])cache.elementAt(row))[col];
     public void setHostURL(){
     String url = "jdbc:odbc:VideoLibrary";
     closeDB();
          try{
db=DriverManager.getConnection(url,"","");
statement=db.createStatement();
catch(Exception e){
System.out.println("Could not initialize the database.");
e.printStackTrace();
public void setQuery(String q){
          cache=new Vector();
String s="select * from Product";
          try{
               ResultSet rs=statement.executeQuery(q);
               ResultSetMetaData meta=rs.getMetaData();
               colCount=meta.getColumnCount();
               headers=new String[colCount];
               for(int h=1;h<=colCount;h++){
                    headers[h-1]=meta.getColumnName(h);
               while(rs.next()){
                    String[] record=new String[colCount];
                    for(int i=0;i<colCount;i++){
                         record[i]=rs.getString(i+1);
                    cache.addElement(record);
               fireTableChanged(null);
          catch(Exception e){
               cache=new Vector();
               e.printStackTrace();
     public void initDB(String url){
          try{
               db=DriverManager.getConnection(url);
               statement=db.createStatement();
          catch(Exception e){
               System.out.println("Could not initialize the database.");
               e.printStackTrace();
     public void closeDB(){
          try{
               if(statement!=null){
               statement.close();
               if(db!=null){
               db.close();
          catch(Exception e){
               System.out.println("Could not close the current connection.");
               e.printStackTrace();

I did write a simple java program but it is not working please help me.....

This is the program I wrote LineRect just to draw a line a rectangle etc...... Y it is not working How can i used the same program to run without using applet that is by using awt and swing.........Pls Help me.............
import java.awt.*;
import java.io.*;
public class LineRect
{public void paint(Graphics g)
     {g.drawLine(10,10, 50,50);
     g.drawRect(10, 60, 40,30);
     g.fillRect(60,10,30,80);
     g.drawRoundRect(10,100,80,50,10,10);
     g.fillRoundRect(20,110,60,30,5,5);
     g.drawLine(100,10,230,140);
     g.drawLine(100,140,230,10);
<APPLET
CODE =LineRect.class
WIDTH=250
HEIGHT=200>
</APPLET>

There are many significant errors here for instance you are using a class file as if it were an applet yet you do not subclass applet. Your code has no init method (if it is to be an applet). Your best bet is to go through the tutorials one step at a time. One thing to consider is to subclass a JPanel and draw on the jpanel overriding the paintComponent method. This can then be added to a JFrame or a JApplet's contentPane and would allow the same graphics in both. But again, please study the tutorials on all of this, otherwise you will be doing hit-or-miss programming, and that is no way to learn.
Much luck!
Addendum: Also, if you are just beginning in Java programming, I suggest you start with the basics and not with Swing / AWT / graphics programming. Otherwise you will just end up bruised and disappointed. You have to learn to walk before you can run.
Edited by: Encephalopathic on Dec 26, 2007 5:09 AM

Using a UNIX shell script to run a Java program (packaged in a JAR)

Hi,
I have an application (very small) that connects to our database. It needs to run in our UNIX environment so I've been working on a shell script to set the class path and call the JAR file. I'm not making a lot of progress on my own. I've attached the KSH (korn shell script) file code.
Thanks in advance to anyone who knows how to set the class path and / or call the JAR file.
loggedinuser="$(whoami)"
CFG_DIR="`dirname $0`"
EXIT_STATUS=${SUCCESS}
export PATH=/opt/java1.3/bin:$PATH
OLDDIR="`pwd`"
cd $PLCS_ROOT_DIR
java -classpath $
EXIT_STATUS=$?
cd $OLDDIR
echo $EXIT_STATUS
exit $EXIT_STATUS

Hi,
I have an application (very small) that connects to
our database. It needs to run in our UNIX environment
so I've been working on a shell script to set the
class path and call the JAR file.
#!/bin/sh
exec /your/path/to/java -cp your:class:paths:here -MoreJvmOptionsHere your.package.and.YourClass "$@"Store this is a file of any name, e.g. yuckiduck, and then change the persmissions to executechmod a+x yuckiduckThe exec makes sure the shell used to run the script does not hang around until that java program finishes. While this is only a minor thing, it is nevertheless infinite waste, because it does use some resources but the return on that investment is 0.
CFG_DIR="`dirname $0`"You would like to fetch the directory of the installation out of $0. This breaks as soon as someone makes a (soft) link in some other directory to this script and calls it by its soft linked name. Your best bet if you don't know a lot of script programming is to hardcode CFG_DIR.
OLDDIR="`pwd`"
cd $PLCS_ROOT_DIRVery bad technique in UNIX. UNIX supports the notion of a "current directory". If your user calls this program in a certain directory, you should assume that (s)he does this on purpose. Making your application dependent on a start in a certain directory ignores the very helpful concept of 'current directory' and is therefore a bug.
cd $OLDDIRThis has no effect at all because it only affects the next two lines of code and nothing else. These two lines, however, don't depend on the current directory. In particular this (as the cd above) does not change the current directory for the interactive shell your user is working in.
echo $EXIT_STATUS
exit $EXIT_STATUSEchoing the exit status is an interesting idea, but if you don't do this for a very specific purpose, I recommend not to do this for the simple reason that no other UNIX program does it.
Harald.

How to make a Java program that recognises a function of two variables...

How to make a Java program that recognises a function of two variables to assign values to that?
First I will give an example and then do the question.
Ex1.
We have any function, eg.y = x ^ 2 + 1 (read 'y' equals 'x' high to the square), a function of the second degree.
To build the graph of this function attach values to 'x' to find the values of 'y'
And thus mount the pair ordered (x, y) which represents a point on the Cartesian plane.
Assigning values to 'x' 'we can build up a table that gives us the pairs ordered:
We can use any numbers, but arfer interval [-3.3]
X | y = x ^ 2 + 1
-3 | Y = (-3) ^ 2 +1 = 10
-2 | Y = (-2) ^ 2 +1 = 5
-1 | Y = (-1) ^ 2 +1 = 2
0 | y = (0) ^ 2 +1 = 1
1 | y = (1) ^ 2 +1 = 2
2 | y = (2) ^ 2 +1 = 5
3 | y = (3) ^ 2 +1 = 10
We then ordered the pairs:
(-3.10), (-2.5); (-1.2), (0,1), (1,2), (2,5), (3,10)
Tabem that can be represented by a table:
X | y
-3 | Y = 10
-2 | Y = 5
-1 | Y = 2
0 | y = 1
1 | y = 2
2 | y = 5
3 | y = 10
Now I begin to explain my doubts.
See this program:
Ex2
* To change this template, choose Tools | Templates
* And open the template in the editor.
Encontrando_o_valor_de_y package;
* @ Author des Soldat Gottes
Import javax.swing.JOptionPane;
Public class (Main
* @ Param args the command line arguments
Public static void main (String [] args) (
Int x, y;
String x1;
X1 = JOptionPane.showInputDialog ( "We have the function y = x + 1 \ n" +
"Assign a value for 'x',"); / / receives a value for the function y = x + 1
X = Integer.parseInt (x1); / / tranforma String in int
Y = x + 1; / / receives the value of 'x' and calculates' y '
JOptionPane.showMessageDialog (null, "The value of 'y' is: \ t \ t" + y);
/ / Displays the value of 'y'
System.exit (0);
We see that the program receives above a value for 'x' and replaces the function contained in the program, y = x + 1, and so is the value of the variable 'y'.
In: x1 = JOptionPane.showInputDialog ( "We have the function y = x + 1 \ n" +
"Assign a value for 'x',");
The entry is a number and that number is assigned aa ja existing function in the (y = x + 1).
The question is: would it be possible to come to a function?
Ex: the program ask: DIGITE THE FUNCTION?
The USUARIO DIGITARIA A FUNCTION ANY, TYPE: y = x ^ 2 +1
The program would recognize the function and give numerical values to that function as Ex1, at the beginning of this text.
And then to find the values of the x and y launch a table.
It would be possible that?
By invez of entering with a number so that the program sustitua a function ja existing as Ex2, seen above, entering with a function quaquer (type: y = x ^ 2 +1) for the program atribuisse values to that function and then create a table of values as Ex1.
I hope it has been easier to understand my doubts now.
Thank you for your attention!
God bless!

rafaelmenezes wrote:
Thanks for the explanation, could understand what fly said.
But as it applied to a program?
How to create a program that recognizes that the entry coefficients?Are you asking about how to parse out the coefficients from the string "3x^4 + 4x^3 - 8x^2 + 5x^1 + 2x^0"? If you define the format to strictly follow that example, this should get you started:
Strip out the spaces
Split the String on "x^"
That should give you [3, 4+4, 3-8, 2+5, 1+2, 0]
Split each resulting String on "+ | -", preserving the operator as a token so you can apply the correct sign to the coeff.
That should leave you with [3, 4, +, 4, 3, -, 8, 2, +, 5, 1, +, 2, 0]. Every other number is a coeff, the rest are the degrees.
You can strip out the +, since those coeffs are already positive, and strip out the - after negating the following number. This is all assuming that you have to write this yourself. There is no doubt already a library or 5 out there that does this for you.

How to execute MS DOS command through Java program???

Dear Sir,
I want to run a MS-DOS command through my Java program. I have tried "Dir" command but no other command which takes command line args doesn't work at all. Please help.
import java.io.*;
class CommandPrompt
     public static void main(String[] args)
          try
               File file = new File("C:/Temp/Java");
               String[] cmd = {"command.com","/c","md folder"};
               String[] envp = {""};
               Process m;
               String s = "";
               m = Runtime.getRuntime().exec(cmd,null,file);
               BufferedReader buf = new BufferedReader(new InputStreamReader(m.getInputStream()));
               while ((s = buf.readLine())!=null)
                    System.out.println(s);
          catch (Exception ex)
               System.out.println("Exception is "+ex);
               ex.printStackTrace();

1. This forum is for Swing-related issues only. This question should be posted to the "Java Programming" forum.
2. Please enclose your sample code in code blocks; it's much easier to read that way. See here for how it's done: http://forum.java.sun.com/faq.jsp#messageformat
3. Please provide more information, like what error messages you got and what OS you're running. For instance, if you're running WinXP, Win2k or NT4, your command processor should be "cmd.exe", not "command.com". When I made that change, your program worked for me.

Why can't I run my Java program with just the JRE, the JDK is required?

I've recently written 3 programs in Java using the Netbeans IDE with JDK 1.6 as the default Java platform. The compile-time libraries include the Swing Application Framework. I use BuildDesk from ProductiveMe to package the each program into a Windows installer.
When I install the programs on a new computer without a JRE or JDK being present, and attempt to run them I get an error (as expected) stating that there is no JVM. The messages says that I need to install JDK 1.3 or higher. I downloaded the latest JRE onto the new computer and attempted to run the programs and I get the same error message. My question is, why can't I run these programs with just the JRE installed? Why do I need the JDK? When I install the JDK, the programs run fine. The typical user may not have the JDK on their system, but they likely have the JRE if they've run Java programs before.
Is the answer as simple as there must be library functions being used by the programs that belong to the JDK, but not the JRE? I'd rather a user not have to install the JDK verses the JRE because they may also have to update some Windows environment variables.
Thank you for any help on this issue.

915088 wrote:
Thanks for your replies. I further investigated BuildDesk and found an option which allows a JVM check but that check needs the JDK. I stopped the JVM check and rebuilt using BuildDesk and it now only requires the JRE to run the programs. The reason why I use BuildDesk is to package more than just the jar file for the user. BuildDesk allows me to create a installation folder structure as well as include any other files in the build. I could just as well zipped all this together for the user but decided against that method.I don't think anyone will question your usage of an installer tool; that is entirely up to you. But what is questionable is that you have problems with that installer tool and then go look for help in a Java programming forum. The next time, go look for help at the source. If there is no way to acquire help (support, a forum, a mailinglist, anything) then that is a very good reason to not use the product in question.

Swing uimanager affecting all java programs?

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