Java programming(import statement)
My query is that what if i import whole package instead of one class being used in my code.
eg.
if i need " java.awt.Button" in my program code
and my import statement is
import java.awt.*;
will it be reduce execution performance of my program?
or it will reduce only Complie time performance?
Only the compile time performance. All the import statement does is tells the compiler it can use the classes. Try importing a whole swathe of classes into a small program and see what I mean. The resulting class file doesn't bloat.
Similar Messages
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Confused about CLASSPATH and how java handles import statements...
Hello,
I must admit I don't get it. I read the articles about setting CLASSPATH etc. but I still wonder:
If you use an import statement, what does the compiler do? I.e. where does it look for the specified classes? I find it confusing because I see in different locations different .jar files:
C:\jdk1.3.1_03\lib\dt.jar
C:\jdk1.3.1_03\lib\htmlconvertor.jar
C:\jdk1.3.1_03\lib\tools.jar
and also
C:\jdk1.3.1_03\jre\lib\i18n.jar
C:\jdk1.3.1_03\jre\lib\rt.jar
C:\jdk1.3.1_03\jre\lib\jaws.jar
C:\jdk1.3.1_03\jre\lib\sunrassign.jar
Can someone explain me what the purpose is of these files?
And why do I have the same contents in
C:\Program Files\JavaSoft\JRE\1.3.1_03\lib
and in
C:\jdk1.3.1_03\jre\lib
Why is that?
Thanks for answering my questions!
-mikeThanx for the answers, but I still wonder, everyone
here says I need to set the classpath, but I don't.Probably because your classes are already in the class path. The compiler/jvm also look for classes by themselves not just in jar files, when just a directory is supplied in the class path. And a period (".") is a valid directory.
Programs importing different classes compile with no
problem. So what's up with that?
Presumably you are referring to your own code - because they are in the class path.
Second, I still don't understand why the runtime needs
the .jar files. The runtime uses classes, like String, that have to come from somewhere.
This would also mean that end-users
need to set the classpath to the .jar files in their
JRE directory to be able to run programs that import
classes from these .jars. But this is not true, right?No it is true. The end-users will have to set the class path. There are variations on this which make it seem like no class path is set. For instance applets in a browser are java but the end-user does not need to set a class path. That is because the browser knows how to download classes/jars and how to set it up so it uses them. (Actually it uses a class loader, but that is probably more information that you need.)
Because if I make some nice classes myself and import
them, how can I expect my end-user to install these
classes and make a classpath for them?That would be between you and you end-user.
First installation is not part of java. For installation you will have to find something outside of java to accomplish the goal.
Additionally how the class path gets set is OS specific. Java does not deal with that. You will also have to find some way to deal with this (most likely part of the installation.)
There are also variations on this. For example the browser example I gave above. Or using the ext directory. Or creating an executable jar. Or simply setting the class path.
In my understanding it should only be needed in the JDK, not
in the JRE. True or am I mistaken?Mistaken. The class path is needed in the JRE as well. You will need to set it. -
Java Programming - Import Element.jar
Really need help here, hope any java gurus can assist me in this. I'm trying to run a simple programme here:
import element.*;
class MethodDrawing
public static void main(String[] args)
DrawingWindow d = new DrawingWindow(500,500);
d.moveTo(100,100);
d.lineTo(100,150);
After compiling I got an error saying "Package Element does not exist.
After some researches, I understand that I need to set my CLASSPATH to the jar file. Thus, I did the following;
- I inserted element.jar in the directory "c:\cis109\element.jar".
- Program directory "c:\cis109\javacourse\
exercise1\MethodDrawing.java"
- I also set CLASSPATH variable to "c:\cis109\element.jar;c:\javacourse;.\
After all I've done the same error occurs. I'm running on WinXP. Any solutions ?SimonAlicante wrote:
Hey Guys! I am having the same problem. I have come to a real dead-end. Did you manage to work out what the problem is?
Was hoping to get past Chapter 5 today but I have tried everything and can't get anywhere. That CLASSPATH thing is driving me demented!Ok, I assume you're on Windows 2000, XP or Vista (English language).
1 - copy the file MethodDrawing.java* and elements.jar into C:\Temp;
2 - open your command prompt by pressing the 'Start' button, select 'Run', type "cmd" and press the button 'OK';
3 - on the command promt, navigate to C:\Temp:cd C:\Temp4 - compile your java-file: javac -cp .;elements.jar MethodDrawing.java5 - run the compiled class-file: java -cp .;elements.jar MethodDrawingIf you do this exactly as I posted, it will work.
* the file MethodDrawing.java should look exactly like this:
import element.*;
public class MethodDrawing
public static void main(String[] args)
DrawingWindow d = new DrawingWindow(500,500);
d.moveTo(100,100);
d.lineTo(100,150);
}I even uploaded all files necessary to run that code snippet (I also have that book by D. Bailey). You can find it here:
[http://iruimte.nl/tmp/] -
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";
public Jump(String jdbcURL, String user, String pwd, int idleSleep, String logDir) {
dbURL = jdbcURL;
dbuser = user;
dbpasswd = pwd;
this.idleSleep = idleSleep;
manager = new JumpQueueManager(dbURL, dbuser, dbpasswd);
loggerDir = logDir;
//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.....sathyaI 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 -
Sorting Names in a text file using java program
h1. Deleting numbers in a text file, sorting the names and writing in to a new file
h2. Sample data
=================
71234 RAJA
89763 KING
89877 QUEEN
==================
h2. Java Program
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.InputStreamReader;
import java.io.Writer;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
class Sortnames {
public static void main(String args[]) {
try {
ArrayList storeWordList = new ArrayList();
ArrayList storeWordList2 = new ArrayList();
int i;
char c;
String inputfile = "names_konda.txt";
String tempfile = "newdatafile.txt";
String outputfile = "sortedoutput.txt";
StringBuffer strBuff=null;
Writer output = null;
File file =null;
Writer sortedoutput = null;
boolean select =false;
//*********************************************** Reading data from Input file
FileInputStream fstream = new FileInputStream(inputfile);
// Get the object of DataInputStream
DataInputStream in = new DataInputStream(fstream);
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String strLine;
//Read File Line By Line
while ((strLine = br.readLine()) != null) {
storeWordList.add(strLine);
//Close the input stream
in.close();
//*********************************************** Adding only alphabets to buffer and writing to file
file= new File(tempfile);
output = new BufferedWriter(new FileWriter(file));
strBuff = new StringBuffer();
for (Iterator iter = storeWordList.iterator(); iter.hasNext();) {
String s = (String) iter.next();
//System.out.println("String "+s);
for (i = 0; i < s.length() ; i++)
c = s.charAt(i);
if (Character.isLetter(c)) {
strBuff.append(c);
strBuff.append("\n");
String myout = strBuff.toString();
output.write(myout);
output.close();
//============================================== Reading the created file,Sorting and placing in Collections
FileInputStream fstream2 = new FileInputStream(tempfile);
// Get the object of DataInputStream
DataInputStream in2 = new DataInputStream(fstream2);
BufferedReader br2 = new BufferedReader(new InputStreamReader(in2));
String strLine2;
//Read File Line By Line
while ((strLine2 = br2.readLine()) != null) {
storeWordList2.add(strLine2);
Collections.sort(storeWordList2);
//===================================================
File sortedfile = new File(outputfile);
sortedoutput = new BufferedWriter(new FileWriter(sortedfile));
for(int m=0; m<storeWordList2.size(); m++)
if (storeWordList2.get(m).toString().trim().length() > 0)
sortedoutput.write(storeWordList2.get(m).toString());
sortedoutput.write("\n");
sortedoutput.close();
System.out.println("Names Sorted SUCCESFULLY");
br.close();
br2.close();
in.close();
fstream.close();
fstream2.close();
///==========================================
File f1 = new File(tempfile);
boolean success = f1.delete();
if (!success){
System.out.println("failed deletion ");
System.exit(0);
}else{
System.out.println("deleted");
// ==========================================
} catch (Exception e) {//Catch exception if any
System.out.println("Error: " + e);
h2. Thanks and regards
h1. BalaNagaRaju.M
h1. [email protected]Do you have a question? Also see the sticky welcome post on how to post formatted code.
-
Problem in Creating New position in Siebel CRM 7.8 using java program
Hi
We have Siebel CRM with Business Object and Business Component as Position.
Position Business Component has a manadatory pick list Division.
When we try to create a new Position by picking the Divison then we are getting the below error
Logged in OK!
picking the list
in the pick() method before
<Exception>
<Major No.>256</Major No.><Minor No.>21944</Minor No.><Message>An error has occurred picking the current row.
Please continue or ask your systems administrator to check your application configuration if the problem persists.(SBL-DAT-00292)</Message><DetailedMessage>Unknown<DetailedMessage>
<Exception>
<com.siebel.om.sisnapi.i>
<Major No.>256</Major No.><Minor No.>21944</Minor No.><Message>An error has occurred picking the current row.
<Error><ErrorCode>21944</ErrorCode> <ErrMsg>An error has occurred picking the current row.
Please continue or ask your systems administrator to check your application configuration if the problem persists.(SBL-DAT-00292)</Message><DetailedMessage>Unknown<DetailedMessage>
Please continue or ask your systems administrator to check your application configuration if the problem persists.(SBL-DAT-00292)</ErrMsg></Error>
<com.siebel.om.sisnapi.i>
<Error><ErrorCode>21735</ErrorCode> <ErrMsg>Siebel eScript runtime error occurred in procedure 'BusComp_SetFieldValue' of BusComp [Position]:
<Error><ErrorCode>21944</ErrorCode> <ErrMsg>An error has occurred picking the current row.
ConversionError 1616: Undefined and Null types cannot be converted to an object.
Please continue or ask your systems administrator to check your application configuration if the problem persists.(SBL-DAT-00292)</ErrMsg></Error>
(SBL-SCR-00141)</ErrMsg></Error>
<Error><ErrorCode>21735</ErrorCode> <ErrMsg>Siebel eScript runtime error occurred in procedure 'BusComp_SetFieldValue' of BusComp [Position]:
<Error><ErrorCode>21735</ErrorCode> <ErrMsg>Stack trace:
BusComp [Position].BusComp_SetFieldValue(), Line: 1110</ErrMsg></Error>
ConversionError 1616: Undefined and Null types cannot be converted to an object.
</com.siebel.om.sisnapi.i></Exception>
(SBL-SCR-00141)</ErrMsg></Error>
<Error><ErrorCode>21735</ErrorCode> <ErrMsg>Stack trace:
BusComp [Position].BusComp_SetFieldValue(), Line: 1110</ErrMsg></Error>
</com.siebel.om.sisnapi.i></Exception>
at com.siebel.data.SiebelBusComp.pick(SiebelBusComp.java:241)
at siebelconn.main(siebelconn.java:44)
Java program
import com.siebel.data.*;
import com.siebel.data.SiebelException;
class siebelconn {
public static void main (String args [])
SiebelDataBean m_dataBean = null;
SiebelBusObject m_busObject = null;
SiebelBusComp m_busComp = null;
SiebelBusComp picklistBC = null;
try{
m_dataBean = new SiebelDataBean(); //Create Siebel JDB instance
m_dataBean.login("XXXX", "XXX", "XXX");
System.out.println("Logged in OK!");
m_busObject = m_dataBean.getBusObject("Position");
m_busComp = m_busObject.getBusComp("Position");
m_busComp.newRecord(false);
picklistBC = m_busComp.getPicklistBusComp("Division");
picklistBC.clearToQuery();
picklistBC.setViewMode(3);
picklistBC.setSearchSpec("Name", "idmtest");
//picklistBC.executeQuery(true);
picklistBC.executeQuery2(true,true);
if(picklistBC.firstRecord())
System.out.println("picking the list");
picklistBC.pick();
System.out.println("records are there");
m_busComp.setFieldValue("Name","Access GE HQ 11");
m_busComp.writeRecord();
}//if
if(m_busObject!=null)
m_busObject.release();
if(m_busComp!=null)
m_busComp.release();
if(picklistBC!=null)
picklistBC.release();
if(m_dataBean!=null)
m_dataBean.logoff();
catch(Exception e)
System.out.println(e);e.printStackTrace();
if(m_busObject!=null)
m_busObject.release();
if(m_busComp!=null)
m_busComp.release();
if(picklistBC!=null)
picklistBC.release();
try
if(m_dataBean!=null)
m_dataBean.logoff();
}catch(Exception e1){System.out.println(e1);}
Can any body please help us.
ThanksFrom the error code, it looks like you have a scripting error in the BusComp_SetFieldValue event on the Position
business component in your application.
Have you tried to look at that code or to turn of scripting for the application as a total?
Axel -
Executing java program in oracle
Good day everyone!
I created a small java program.
import javax.swing.JOptionPane;
public class LogOn {
public static void main (String [] args) {}
public static void ShowMessage(){
JOptionPane.showConfirmDialog(null, "Hello", "Info", JOptionPane.PLAIN_MESSAGE);
I compiled the code using javac and loaded into oracle using "loadjava -u scott/tiger Logon
Then I created a procedure,
create or replace procedure l_b
as language java
name 'LogOn.showMessage()';
then I executed the procedure
SQL> execute l_b;
it's just say
ERROR at line 1:
ORA-03113: end-of-file on communication channel
Any idea why its doing that?
Thanks for the time
Edited by: Xtro on Oct 30, 2008 9:38 AMWhat is the "warning banner" attempting to communicate? And where did this requirement come from-- presumably users are not seeing a banner when they log in today.
Realistically, you are not going to be able to cause arbitrary client applications to display something, you are going to have to configure each client application separately, which seems like a huge investment of time for very marginal benefits assuming that government agencies have a decent number of client machines and a decent variety of client applications. The glogin.sql file will work for SQL*Plus (assuming very recent versions or that no one uses the "connect" command to connect to a different database), but I believe you are looking for something that works across client applications, which probably doesn't exist.
Justin -
How do i use an import statement in a java program
I need to write a java program which will connect to the Database but i need to do an import like in DB2 which will load data to the table.
How do i execute that import statementAre you saying that you need to add rows to a table in DB2 via a Java program? If so, you need to look at the JDBC API, (available on this site along with a bunch of tutorials). If not, post again with a clearer description of your problem.
-
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 QueryTableModelhere'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(); -
Program Problems...Import Statement needed?
I am currently a student at DeVry University, and today I had my java class where my professor played a video on java programming for us made by a group called "CBTNuggets". The video went over Inner classes and the professor had us copy the code as the person in the video was typing it up. While attempting to compile the code I encountered several compiler errors on the second of the two files I had typed, I am going to first post the source code for both files, and then follow that with the compiler errors that were generated when I attempted to compile the code. If anyone is able to assist me with this I would greatly appreciate it, I think I may need to add an import statement ;however, I do not know how to implement one for user defined Inner Classes:
Invoice.java was the file that contained the Inner classes
* Invoice.java
* Created on February 1, 2007, 1:39 PM
* To change this template, choose Tools | Template Manager
* and open the template in the editor.
* @author vontux
import java.util.*;
public class Invoice {
private String strCustName;
private String strCustAddr;
private int intInvoiceNum;
private Date dtInvoiceDate;
/** Creates a new instance of Invoice */
Invoice(String sCN, String sCA, int iN, Date dt)
strCustName = sCN;
strCustAddr = sCA;
intInvoiceNum = iN;
dtInvoiceDate = dt;
class InvoiceItem //enclosed class
private int intLineItem;
private int intItemID;
private int intUnits;
private String strItemDesc;
InvoiceItem(int li, int id,String desc, int iu)
intLineItem = li;
intItemID = id;
intUnits = iu;
strItemDesc = desc;
public void showInvoice()
System.out.println("Customer Name: " + Invoice.this.strCustName);
System.out.println("Item Description: " + strItemDesc);
}UseInvoice.java is the class that is supposed to create objects of the Inner classes from Invoice.java and then run the code:
* UseInvoice.java
* Created on February 1, 2007, 1:51 PM
* To change this template, choose Tools | Template Manager
* and open the template in the editor.
* @author vontux
import java.util.*;
public class UseInvoice {
public static void main(String[] args)
Date today = new Date();
Invoice myInvoice = new Invoice("Robert Barrr", "12345 N. CBTNuggets Dr.", 321,today );
Invoice.InvoiceItem myInvItem = myInvoice.new InvoiceItem(1, 345,"Toy Train", 2);
myInvItem.showInvoice();
/** Creates a new instance of UseInvoice */
public UseInvoice() {
}And here are the compiler errors that I recieved:
C:\Documents and Settings\Matt\Desktop\temptemp\temp\UseInvoice.java:19: cannot
find symbol
symbol : class Invoice
location: class UseInvoice
Invoice myInvoice = new Invoice("Robert Barrr", "12345 N. CBTNuggets Dr.
", 321,today );
^
C:\Documents and Settings\Matt\Desktop\temptemp\temp\UseInvoice.java:19: cannot
find symbol
symbol : class Invoice
location: class UseInvoice
Invoice myInvoice = new Invoice("Robert Barrr", "12345 N. CBTNuggets Dr.
", 321,today );
^
C:\Documents and Settings\Matt\Desktop\temptemp\temp\UseInvoice.java:20: package
Invoice does not exist
Invoice.InvoiceItem myInvItem = myInvoice.new InvoiceItem(1, 345,"Toy Tr
ain", 2);
^
3 errorsThere are no errors occurs when I compile this two java files .
Here are the result I'm using jdk1.6 and dos command
[output]
[search path for source files: [D:\J2SDK1.6.0\lib, .\out]]
[search path for class files: [D:\J2SDK1.6.0\jre\lib\resources.jar, D:\J2SDK1.6.0\jre\lib\rt.jar, D:\J2SDK1.6.0\jre\lib\sunrsasign.jar, D:\J2SDK1.6.0\jre\lib\jsse.jar, D:\J2SDK1.6.0\jre\lib\jce.jar, D:\J2SDK1.6.0\jre\lib\charsets.jar, D:\J2SDK1.6.0\jre\classes, D:\J2SDK1.6.0\jre\lib\ext\dnsns.jar, D:\J2SDK1.6.0\jre\lib\ext\localedata.jar, D:\J2SDK1.6.0\jre\lib\ext\sunjce_provider.jar, D:\J2SDK1.6.0\jre\lib\ext\sunmscapi.jar, D:\J2SDK1.6.0\jre\lib\ext\sunpkcs11.jar, D:\J2SDK1.6.0\lib, .\out]]
[parsing started .\Invoice.java]
[parsing completed 31ms]
[parsing started .\UseInvoice.java]
[parsing completed 15ms]
[loading D:\J2SDK1.6.0\lib\ct.sym(META-INF/sym/rt.jar/java/lang/Object.class)]
[loading D:\J2SDK1.6.0\lib\ct.sym(META-INF/sym/rt.jar/java/lang/String.class)]
[loading D:\J2SDK1.6.0\lib\ct.sym(META-INF/sym/rt.jar/java/util/Date.class)]
[checking Invoice]
[loading D:\J2SDK1.6.0\lib\ct.sym(META-INF/sym/rt.jar/java/lang/System.class)]
[loading D:\J2SDK1.6.0\lib\ct.sym(META-INF/sym/rt.jar/java/io/PrintStream.class)]
[loading D:\J2SDK1.6.0\lib\ct.sym(META-INF/sym/rt.jar/java/io/FilterOutputStream.class)]
[loading D:\J2SDK1.6.0\lib\ct.sym(META-INF/sym/rt.jar/java/io/OutputStream.class)]
[loading D:\J2SDK1.6.0\lib\ct.sym(META-INF/sym/rt.jar/java/io/Serializable.class)]
[loading D:\J2SDK1.6.0\lib\ct.sym(META-INF/sym/rt.jar/java/lang/StringBuilder.class)]
[loading D:\J2SDK1.6.0\lib\ct.sym(META-INF/sym/rt.jar/java/lang/AbstractStringBuilder.class)]
[loading D:\J2SDK1.6.0\lib\ct.sym(META-INF/sym/rt.jar/java/lang/CharSequence.class)]
[loading D:\J2SDK1.6.0\lib\ct.sym(META-INF/sym/rt.jar/java/lang/Comparable.class)]
[loading D:\J2SDK1.6.0\lib\ct.sym(META-INF/sym/rt.jar/java/lang/StringBuffer.class)]
[wrote .\out\Invoice$InvoiceItem.class]
[wrote .\out\Invoice.class]
[checking UseInvoice]
[loading D:\J2SDK1.6.0\lib\ct.sym(META-INF/sym/rt.jar/java/lang/Class.class)]
[wrote .\out\UseInvoice.class]
[total 734ms]
[output]
check your syntax to compile these two files, may be you can show your syntax to compile these two files
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