Develop Reference

JavaFX application with JDBC in NetBeans don't start

I work on a small educational project - easy java app with database and gui. I work in NetBeans IDE.
For graphical interface I use JavaFX, and as I've testet this part work perfectly fine, but I have some problem with JDBC part (I use JDBC driver for sqlite database, created with DB browser for sqlite). My main application class looks like this:
public class BazaLyoko extends Application {
#Override
public void start(Stage stage) throws Exception {
Database baza = new Database();
String tytul = baza.getEpisodeName(1);
stage.setTitle(tytul);
Parent root = FXMLLoader.load(getClass().getResource("FXMLDocument.fxml"));
Scene scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
launch(args);
}
}
And when I change those lines:
Database baza = new Database();
String tytul = baza.getEpisodeName(1);
To this (to replace value retrieved from database to a placeholder - I did this to ensure if the error is rather connected with JavaFX or JDBC part)
String tytul = "";
Program start without problem, but when I try to use my database application don't start. There isn't any compilation error or anything like that (or maybe I just don't see them, as I'm quite new to this IDE, though I think such things are usually blatantly visible) just no application window appear.
Here's the code for my database class(they both share the same package):
public class Database {
public static Connection conn;
public Database()
{
connect();
}
public static void connect()
{
String connectionString = "jdbc:sqlite:BazaLyoko.db";
try
{
conn = DriverManager.getConnection(connectionString);
if (conn != null)
{
DatabaseMetaData meta = conn.getMetaData();
//System.out.println("Nazwa sterownika to " + meta.getDriverName());
//System.out.println("Stworzono baze danych.");
}
}
catch (SQLException e)
{
System.out.println(e.getMessage());
}
}
private ResultSet doQuery(String query) throws SQLException
{
Statement stmt = null;
try
{
stmt = this.conn.createStatement();
ResultSet result = stmt.executeQuery(query);
return result;
}
catch (SQLException e )
{
throw new Error("Problem", e);
}
finally
{
if (stmt != null) { stmt.close(); }
}
}
public String getEpisodeName(int nr) throws SQLException
{
ResultSet result = doQuery("SELECT tytul FROM Odcinki WHERE numer="+String.valueOf(nr));
result.next();
return result.getString("tytul");
}
}
Database of that name is located inside my project directory (i also tried to copy it to package directory but nothing changed), the names of the table and column are correct to and exist a row with value 1 in column numer.
What I'm missing or doing wrong?
Edit:
I manage to get the following Stack Trace:
No suitable driver found for jdbc:sqlite:BazaLyoko.db
at com.sun.corba.se.impl.util.Utility.printStackTrace(Utility.java:933)
at bazalyoko.Database.connect(Database.java:46)
at bazalyoko.Database.<init>(Database.java:26)
at bazalyoko.BazaLyoko.start(BazaLyoko.java:23)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$8(LauncherImpl.java:863)
at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$7(PlatformImpl.java:326)
at com.sun.javafx.application.PlatformImpl.lambda$null$5(PlatformImpl.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$6(PlatformImpl.java:294)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$4(WinApplication.java:186)
at java.lang.Thread.run(Thread.java:748)
Exception in Application start method
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:389)
at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:328)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:767)
Caused by: java.lang.RuntimeException: Exception in Application start method
at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$1(LauncherImpl.java:182)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.NullPointerException
at bazalyoko.Database.doQuery(Database.java:57)
at bazalyoko.Database.getEpisodeName(Database.java:75)
at bazalyoko.BazaLyoko.start(BazaLyoko.java:24)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$8(LauncherImpl.java:863)
at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$7(PlatformImpl.java:326)
at com.sun.javafx.application.PlatformImpl.lambda$null$5(PlatformImpl.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$6(PlatformImpl.java:294)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$4(WinApplication.java:186)
... 1 more
Exception running application bazalyoko.BazaLyoko
Java Result: 1

Exception java.lang.NoClassDefFoundError android/app/Activity

In an android app, having:
public class Pars extends Activity{
public Document docout(){
InputStream is = getResources().openRawResource(R.raw.talechap01);
Document docout = null;
DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = null;
try {
builder = domFactory.newDocumentBuilder();
docout = builder.parse(is);
} catch (ParserConfigurationException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (SAXException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return docout;
}
and
public class Manager {
public static String getStory(String spage, Document docs) {
XPathExpression expr;
XPath xpath = XPathFactory.newInstance().newXPath();
Object result = null;
String num = spage;
String par = null;
try {
expr = xpath.compile("//decision"+num+"/p//text()");
result = expr.evaluate(docs, XPathConstants.NODESET);
}
catch (XPathExpressionException e) {
e.printStackTrace();
}
NodeList nodes = (NodeList) result;
for (int i = 0; i < nodes.getLength(); i++) {
par = nodes.item(i).getNodeValue();
System.out.println(par);
}
return par;
}
}
Now I want to test the code.
public class Test {
public static void main(String[] args) {
try {Pars p = new Pars();
Document doc = p.docout();
System.out.println(Manager.getStory("000", doc));
}catch (Exception e){
e.printStackTrace();
}
}
}
I run "Test" as a java application and I get:
Exception in thread "main" java.lang.NoClassDefFoundError:
android/app/Activity at java.lang.ClassLoader.defineClass1(Native
Method) at java.lang.ClassLoader.defineClass(Unknown Source) at
java.security.SecureClassLoader.defineClass(Unknown Source) at
java.net.URLClassLoader.defineClass(Unknown Source) at
java.net.URLClassLoader.access$100(Unknown Source) at
java.net.URLClassLoader$1.run(Unknown Source) at
java.net.URLClassLoader$1.run(Unknown Source) at
java.security.AccessController.doPrivileged(Native Method) at
java.net.URLClassLoader.findClass(Unknown Source) at
java.lang.ClassLoader.loadClass(Unknown Source) at
sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) at
java.lang.ClassLoader.loadClass(Unknown Source) at
com.stack.over.Test.main(Test.java:11) Caused by:
java.lang.ClassNotFoundException: android.app.Activity at
java.net.URLClassLoader$1.run(Unknown Source) at
java.net.URLClassLoader$1.run(Unknown Source) at
java.security.AccessController.doPrivileged(Native Method) at
java.net.URLClassLoader.findClass(Unknown Source) at
java.lang.ClassLoader.loadClass(Unknown Source) at
sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) at
java.lang.ClassLoader.loadClass(Unknown Source) ... 13 more
I tried to find how to fix it but cannot achieve it.
I have this answer from another question but I'm kind of noob yet and can't figure it out how to fix it.
You have defined your Pars class as extending the class Activity. The
error you are seeing is telling you that the class
android.app.Activity is not available on the classpath. Maybe you need
to check which libraries you import. – adamretter Mar 5 at 10:01
Thanks all.

The error is that you're trying to run a program that references Android classes (android.app.Activity) as a regular Java program that doesn't have Android runtime libraries in its classpath.
You should run Android apps as Android apps (on an emulator or a device) and regular Java programs as regular Java programs and not mix the two. Activity is Android; main() method is regular Java.
To learn Android app development, you can start with the developer.android.com getting started documentation.

The error message says it all. You are writing Android now. Trying to write a main method doesn't make any more sense in Android than it would if you were writing a webapp that runs in Tomcat. You are going to need to step back and read up on how Android works.

Using Custom Fonts [java.io.IOException: Error reading font data.]

The title doesn't allow me to say Problem, so the actual error message was -
java.io.IOException: Problem reading font data.
at java.awt.Font.createFont(Unknown Source)
at AddFont.createFont(AddFont.java:11)
at MainFrame$1.run(MainFrame.java:105)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$000(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
The code is -
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
try {
AddFont addFont = new AddFont();
addFont.createFont();
} catch (Exception e) {
e.printStackTrace();
}
createGUI();
} //public void run() Closing
});
}
and the file that I used to get the AddFont addFont-
import java.awt.Font;
import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.InputStream;
public class AddFont extends MainFrame{
public void createFont(){
Font ttfBase = null;
Font telegraficoFont = null;{
try {
InputStream myStream = new BufferedInputStream(new FileInputStream(FONT_PATH_TELEGRAFICO));
ttfBase = Font.createFont(Font.TRUETYPE_FONT, myStream);
telegraficoFont = ttfBase.deriveFont(Font.PLAIN, 24);
} catch (Exception ex) {
ex.printStackTrace();
System.err.println("Font not loaded.");
}
}
}
}
I was instructed to make a new thread because this is a separate problem from my other one.
Why am I getting this problem, and how can I fix it?
I have my TELEGRAFICO.TTF font in my imageFolder, which is really just my resources folder. I use
public static final String FONT_PATH_TELEGRAFICO = "imageFolder/TELEGRAFICO.TTF";
to call in my path.
What am I doing wrong?
EDIT - I no longer get that error message, and I don't get "Font not loaded". How can I use the font in other class files other than the one I made that method in?
(I want to use that font on buttons in multiple class files. I tried using it here -
regButton = new JButton();
regButton.setText("Foo");
regButton.setAlignmentX(Component.CENTER_ALIGNMENT);
regButton.setFont(telegraficoFont);
But it said telegraficoFont cannot be resolved to a variable. (Because it was in a different class file.)
How can I fix this? Thanks again for the help.

In some cases the cause is the running instance not being able to write to the Java temp directory (java.io.tmpdir).
If your are running it on tomcat maybe you deleted the temp directory of the tomcat installation, or the folder have wrong permissions.
(tomcat folder)/temp

As you have a problem with possible font file locating and font stream creation,
Try this >> Issue loading custom font AND http://forums.devshed.com/showpost.php?p=2268351&postcount=2
To answer your question "how to make this function easy to use everywhere", do as this:
public class AddFont extends MainFrame {
private static Font ttfBase = null;
private static Font telegraficoFont = null;
private static InputStream myStream = null;
private static final String FONT_PATH_TELEGRAFICO = "imageFolder/TELEGRAFICO.TTF";
public Font createFont() {
try {
myStream = new BufferedInputStream(
new FileInputStream(FONT_PATH_TELEGRAFICO));
ttfBase = Font.createFont(Font.TRUETYPE_FONT, myStream);
telegraficoFont = ttfBase.deriveFont(Font.PLAIN, 24);
} catch (Exception ex) {
ex.printStackTrace();
System.err.println("Font not loaded.");
}
return telegraficoFont;
}
}
And then in your calling class:
public class Test {
public static Font font = null;
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
try {
if (font == null) {
font = AddFont.createFont();
}
} catch (Exception e) {
e.printStackTrace();
}
createGUI();
} // public void run() Closing
});
}
}

In some cases, maybe the Fontconfig is lack in your running environment. After installing, everything is OK.
For example,
yum install fontconfig

you could try to install "dejavu-sans-fonts" and fontconfig, it works

NoClassDefFoundError while trying to use NxParser

I am trying to read a N-Triples (.nt) DBpedia file with NxParser, but I had the following error, and I don't know what to do.
Exception in thread "main" java.lang.NoClassDefFoundError: org/semanticweb/yars/nx/parser/NxParser$1
at org.semanticweb.yars.nx.parser.NxParser.stringItFromBufferedReader(Unknown Source)
at org.semanticweb.yars.nx.parser.NxParser.<init>(Unknown Source)
at org.semanticweb.yars.nx.parser.NxParser.<init>(Unknown Source)
at SentencesMatching_prova.main(SentencesMatching_prova.java:29)
Caused by: java.lang.ClassNotFoundException: org.semanticweb.yars.nx.parser.NxParser$1
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
... 4 more
The source code of the script is:
import java.io.*;
import org.semanticweb.yars.nx.parser.*;
public class SentencesMatching_prova {
public static void main(String[] args) {
try {
String relationFileName = "../zzz-trash/revisions_en.nt";
FileInputStream is = new FileInputStream(relationFileName);
NxParser nxp = new NxParser(is);
while (nxp.hasNext()) {
// do stuff
}
} catch (Exception ex) {
ex.printStackTrace(System.out);
}
}
}

Java HTMLUnit MalformedURLException

I'm trying to execute this code from the HTMLUnit tutorial:
final WebClient webClient = new WebClient();
final HtmlPage page = webClient.getPage("http://htmlunit.sourceforge.net");
but I get the MalformedURLException in the second line when saving it in Eclipse (if I compile and run the code, I get it too). What's the problem? TIA
PS: I'm new to Java
Up:
Here's the stack trace:
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/httpclient/auth/CredentialsProvider
at Tester.main(Tester.java:12)
Caused by: java.lang.ClassNotFoundException: org.apache.commons.httpclient.auth.CredentialsProvider
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
... 1 more

I tried this in Eclipse 3.5 and it is working correctly, and the test is passing. I assume that you have included the necessary HTMLUnit JARs into your project? I took all the JARs from the HTMLUnit lib directory and added them to the build path of my project.
Also, can you catch the exception and post the stack trace here?
try {
final WebClient webClient = new WebClient();
final HtmlPage page = webClient.getPage("http://htmlunit.sourceforge.net");
assertEquals("HtmlUnit - Welcome to HtmlUnit", page.getTitleText());
}
catch (Exception e) {
e.printStackTrace();
}

package com.project.test;
import java.io.IOException;
import java.net.MalformedURLException;
import com.gargoylesoftware.htmlunit.FailingHttpStatusCodeException;
import com.gargoylesoftware.htmlunit.WebClient;
import com.gargoylesoftware.htmlunit.html.HtmlPage;
public class Practice1 {
public static void main(String[] args) {
final WebClient webClient = new WebClient();
HtmlPage page;
try {
page = (HtmlPage) webClient.getPage("http://htmlunit.sourceforge.net");
System.out.println("Title="+ page.getTitleText());
} catch (FailingHttpStatusCodeException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

Since in your stacktrace you have
Caused by: java.lang.ClassNotFoundException: org.apache.commons.httpclient.auth.CredentialsProvider
this isn't a malformed URL exception.
As confirmed by JARFinder, org.apache.commons.httpclient.auth.CredentialsProvider class should come from commons-httpclient-3.*.jar. Thus the cause of the problem must be that you don't have Commons HTTPClient 3.x JARs in your classpath.