Ramu Ramaiah

I have gone through the Interface description in Java API documentation. I did not understand the whole picture, what is the significance of the interface.

The documentation says "This interface is implemented by an object that can provide a Reference to itself". If an object wants to provide a reference to itself, one can always have a object of the same type as a member and store a this reference right? Why should we have to implement this interface?

Hi,

Can somebody explain the purpose of Referenceable interface and it's significance?

Thanks,
Ramu

I am getting the following exception when I try to run JBoss. Can anyone please help me?

Thanks,
Ramu

[pre]
Failed to boot JBoss:
org.jboss.deployment.DeploymentException: - nested throwable: (java.lang.reflect.UndeclaredThrowableException)
at org.jboss.system.ServiceConfigurator.install(ServiceConfigurator.java:196)
at org.jboss.system.ServiceController.install(ServiceController.java:226)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155)
at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94)
at org.jboss.mx.server.Invocation.invoke(Invocation.java:86)
at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659)
at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210)
at $Proxy4.install(Unknown Source)
at org.jboss.deployment.SARDeployer.create(SARDeployer.java:249)
at org.jboss.deployment.MainDeployer.create(MainDeployer.java:969)
at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:818)
at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:782)
at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:766)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155)
at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94)
at org.jboss.mx.interceptor.AbstractInterceptor.invoke(AbstractInterceptor.java:133)
at org.jboss.mx.server.Invocation.invoke(Invocation.java:88)
at org.jboss.mx.interceptor.ModelMBeanOperationInterceptor.invoke(ModelMBeanOperationInterceptor.java:142)
at org.jboss.mx.server.Invocation.invoke(Invocation.java:88)
at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659)
at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210)
at $Proxy5.deploy(Unknown Source)
at org.jboss.system.server.ServerImpl.doStart(ServerImpl.java:482)
at org.jboss.system.server.ServerImpl.start(ServerImpl.java:362)
at org.jboss.Main.boot(Main.java:200)
at org.jboss.Main$1.run(Main.java:490)
at java.lang.Thread.run(Thread.java:595)
Caused by: java.lang.reflect.UndeclaredThrowableException
at org.jboss.system.ServiceCreator.install(ServiceCreator.java:236)
at org.jboss.system.ServiceConfigurator.internalInstall(ServiceConfigurator.java:449)
at org.jboss.system.ServiceConfigurator.install(ServiceConfigurator.java:171)
... 36 more
Caused by: java.lang.NoClassDefFoundError: org/jboss/util/threadpool/ThreadPool
at org.jboss.naming.NamingService.<init>(NamingService.java:75)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:494)
at org.jboss.mx.server.MBeanServerImpl.instantiate(MBeanServerImpl.java:1233)
at org.jboss.mx.server.MBeanServerImpl.instantiate(MBeanServerImpl.java:286)
at org.jboss.system.ServiceCreator.install(ServiceCreator.java:193)
... 38 more
[/pre]

This one worked.

<xsl:variable name="A"><xsl:value-of select=' "0x9223" '/></xsl:variable>

I think for strings we have to insert the double quoted strings in single quotes.

Thanks,
Ramu

Hi,

I have the following XML content.

<?xml version="1.0"?> <?xml-stylesheet type="text/xsl" href="log.xsl"?> <E t="2006-06-20 16:46:18.285" es="5" ep="0x9223" ei="0x5" ie="0x0" ii="0x0"><![CDATA[ Data ]]></E>

I have to convert the XML in to a html display when the ep is "0x9223". I wrote the following XSLT, "log.xsl"

<xsl:stylesheet version = '1.0' xmlns:xsl='http://www.w3.org/1999/XSL/Transform'> <xsl:variable name="A" select="string(0x9223)"/> <xsl:template match="/"> <xsl:apply-templates select="//E"/> </xsl:template> <xsl:template match="E"> <div style="color:navy"> <xsl:for-each select="."> <xsl:if test="string(@ep)=$A"> <xsl:value-of select="string(@ep)"/> </xsl:if> </xsl:for-each> </div> </xsl:template> </xsl:stylesheet>

When I try to open the XML, I am getting a error in <xsl:variable name="A" select="string(0x9223)"/>. can somebody help me how to convert the hexadecimal literal to string?

Thanks,
Ramu

Hi,

I am trying to write a simple editor. Please see below for the code. When I try to open a big file of size more than 1 MB, I am getting the above exception.

package swing_programs; import java.awt.*; import java.awt.event.ActionEvent; import java.io.*; import javax.swing.*; import javax.swing.filechooser.*; import javax.swing.text.*; import javax.swing.text.IconView; public class Editor extends JFrame { private JTextComponent textComp; private Action openAction = new OpenAction(); public static void main(String[] args) throws Exception { Editor editor = new Editor(); editor.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setDefaultLookAndFeelDecorated(true); UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel"); editor.setVisible(true); } // Create an editor. public Editor() { super("Editor"); textComp = createTextComponent(); JScrollPane scrollPane = new JScrollPane(textComp); Container content = getContentPane(); content.add(scrollPane, BorderLayout.CENTER); setJMenuBar(createMenuBar()); setSize(800, 600); } // Create the JTextComponent subclass. protected JTextComponent createTextComponent() { JTextArea ta = new JTextArea(); ta.setLineWrap(true); return ta; } // Subclass can override to use a different open action. protected Action getOpenAction() { return openAction; } // Create a JMenuBar with file & edit menus. protected JMenuBar createMenuBar() { JMenuBar menubar = new JMenuBar(); JMenu file = new JMenu("File"); menubar.add(file); file.add(getOpenAction()); return menubar; } // An action that opens an existing file class OpenAction extends AbstractAction { public OpenAction() { super("Open", new ImageIcon("icons/open.gif")); } // Query user for a filename and attempt to open and read the file into // the // text component. public void actionPerformed(ActionEvent ev) { String file = null; //code to get the file FileReader reader = null; BufferedReader bufRead = null; try { reader = new FileReader(file); bufRead = new BufferedReader(reader); textComp.read(bufRead, "InputFile"); } catch (IOException ex) { JOptionPane.showMessageDialog(Editor.this, "File Not Read", "ERROR", JOptionPane.ERROR_MESSAGE); } finally { if (reader != null) { try { reader.close(); } catch (IOException x) { } } } } } }

Can somebody help me figure out, is there any alternate technique to avoid this kind or problem?

Thanks,
Ramu

Hi Please find the code below.

package Mock; public class Basket<E> { private E element; public void setElement(E x) { element = x; } public E getElement() { return element; } public String toString() { System.out.println(element); return "My Basket..."; } } class Apple { } class GoldenDelicious extends Apple {} class Jonagold extends Apple {} class AppleHelper { public static boolean isRipe(Apple apple) { return true; } public static boolean isRipeInBasket(Basket<? extends Apple> basket) { Apple apple = basket.getElement(); // 1 return isRipe(apple); // 2 } } class Test { public static void main(String[] args) { Basket<? extends Apple> b1 = new Basket<GoldenDelicious>(); Basket<? extends Apple> b2 = new Basket<Jonagold>(); b1.setElement(new GoldenDelicious()); b2.setElement(new Jonagold()); AppleHelper help = new AppleHelper(); System.out.println(help.isRipeInBasket(b1)); System.out.println(help.isRipeInBasket(b2)); System.out.println("End..."); } }

The below two calls to methods gives a compilation error.
b1.setElement(new GoldenDelicious());
b2.setElement(new Jonagold());

I don't understand why it is doing so, since the type of the baskets b1 and b2 is "anything which extends Apple".

Thanks Joanne.

Hi,

I am a beginner to Java programming language. I am trying to learn the new "generics" functionality added to Java 5.0.

I came accross this peice of code from http://java.sun.com/developer/technicalArticles/J2SE/generics/

void printCollection(Collection<?> c) {
for(Object o:c) {
System.out.println(o);
}
}

I did not understand the syntax "Object o:c".
Can somebody explain what this means?

Thanks,
Ramu