Comments(0) Basic:
List<string> ls1 = new ArrayList</string><string>(); //Create a generic list of strings ls1.add("hello"); ls1.add(new Integer(2)); // no can do, because the type is string List<object> ls2 = new ArrayList<string>(); </string></object></string>
Comments(0) class A implements Runnable { public void run() { System.out.println(Thread.currentThread().getName()); } } class B implements Runnable { public void run() { new A().run(); new Thread(new A(), "name_thread2").run(); new Thread(new A(), "name_thread3").start(); } } public class Main { public static void main(String[] args) { new Thread(new B(), "name_thread1").start(); } }
What is the output? Continue »
Comments(0) 1. Dropbox. “Your files, wherever you need them“. Dropbox is a folder on your computer that gives you access to the latest version of your files from any computer. If you haven’t tried this, I strongly suggest you start using it. It is free for 2GB.
2. A good java studying website: www.javaranch.com. The good thing about this website is its forum, which provide a nice platform for users to communicate. And unlike the code format in the real exam, its code is colored, so it’s comfortable to read. One more good point about it, is its amount of users. So many people are using it, so you can get info from many people.
3. If you want to link to a specific part of a video on YouTube, you can. For example,
http://www.youtube.com/watch?v=PjDw3azfZWI#t=31m08s
Notice the “#t=31m08s” on the end of the url? That link will take you 31 minutes and 8 seconds into that video. Linking to a particular minute and second can be really helpful — for example, that link takes you straight to where someone asks Eric Schmidt a question about Twitter.
Comments(0) Object type (not the reference variable's type), determines which overridden method is used at runtime
Reference type determines which overloaded method will be used at compile time.
Polymorphism applies to overriding, not to overloading.
Here is an example of overridding. After reading the code, guess the output. Easy!
Comments(0) Any checked exceptions that may be thrown in a method must either be caught or declared in the method’s throws clause. Checked exceptions are so called because both the Java compiler and the Java virtual machine check to make sure this rule is obeyed.
Comments(0) I got this from JavaRanch, can not hesitate to put it here.
What is a Web Service?
In simple terms a Web Service is an application or business logic that is accessible using standard Internet protocols.
Can I access a web services from any application?
Yes, if your application supports XML based object request and response.
Are there any real web services available for testing?
Yes, check http://xmethods.net/
What is the best Web Service Testing tools?
I would say SoapUI, it is perfectly for installation and implementation. Now if you know some about Web Service, you can start practice with SoupUI and xmethods.net. This can help you understand Web Service.
What are the current free and commercial implementations available for Web Services?
Web Service protocols and supporting package
Can I access a web service from within a browser?
You can use the JavaScript XmlHttpRequest object (read introductions here and here). You’ll have to create and process the XML requests and responses yourself, though. This works in Internet Explorer, Safari and Mozilla-based browsers like FireFox.
What are the differences between JAX-RPC, JAX-WS, Apache Axis, SAAJ, Apache SOAP, JWSDP, Metro, Jersey and GlassFish?
Where can I find the relevant standards?
Some useful code snippets
Which other software packages help implement Java Web Services?
More articles on specific topics
Check the JavaRanch Bunkhouse Web Services And SOAP category.
The book title is linked to the publisher where sample content may reside. The ISBN links to Amazon US which tends to list reviews.
SOA Using Java™ Web Services (2007) ISBN 0130449687 Web page Bunkhouse Review
RESTful Web Services (2007) ISBN 0596529260
J2EE Web Services (2004) ISBN 0321146182 Bunkhouse Review Author’s Blog
Designing Web Services with the J2EE™ 1.4 Platform (2004) ISBN 0321205219 On-line Version PDF Version
Service-Oriented Architecture: Concepts, Technology, and Design (2005) ISBN 0131858580 Web page
Service-Oriented Architecture: A Field Guide to Integrating XML and Web Services (2004) ISBN 0131428985 Web page
SOA Principles of Service Design (2007) ISBN 0132344823 Web page
SOA in Practice: The Art of Distributed System Design (2007) ISBN 0596529554 Web page
Java Web Services in a Nutshell
Building Web Services with Java: Making Sense of XML, SOAP, WSDL, and UDDI
Developing Web Services with Apache Axis
Developing Java Web Services: Architecting and Developing Secure Web Services Using Java
Comments(3) I was trying to do a java web service project which allows users to upload files through web service. After searching for several days, I realized that, this is not a good idea. In face, web service can transfer Image from end to end, but not for large regular files, such as pdf, doc, etc. The reason is that server will read file to byte array which consumes much memory. If many users use it at the same time, this may lead to scalability issue.
Comments(0) 1. The first one is simple as following:
public class ThreadA { public static void main(String[] args){ ThreadB b = new ThreadB(); b.start(); synchronized(b){ try{ System.out.println("Waiting for b to complete..."); b.wait(); }catch(InterruptedException e){e.printStackTrace();} System.out.println("Total is: " + b.total); } } } class ThreadB extends Thread{ int total; @Override public void run(){ synchronized(this){ for(int i=0; i<100 ; i++){ total += i; } notify(); } } }
2. The second is more complex, see the comments.
import java.util.Vector; class Producer extends Thread { static final int MAXQUEUE = 5; private Vector messages = new Vector(); @Override public void run() { try { while (true) { putMessage(); sleep(5000); } } catch (InterruptedException e) { } } private synchronized void putMessage() throws InterruptedException { while (messages.size() == MAXQUEUE) { wait(); } messages.addElement(new java.util.Date().toString()); notify(); //Later, when the necessary event happens, the thread that is running it calls notify() from a block synchronized on the same object. } // Called by Consumer public synchronized String getMessage() throws InterruptedException { notify(); while (messages.size() == 0) { wait();//By executing wait() from a synchronized block, a thread gives up its hold on the lock and goes to sleep. } String message = (String) messages.firstElement(); messages.removeElement(message); return message; } } class Consumer extends Thread { Producer producer; Consumer(Producer p) { producer = p; } @Override public void run() { try { while (true) { String message = producer.getMessage(); System.out.println("Got message: " + message); //sleep(200); } } catch (InterruptedException e) { e.printStackTrace(); } } public static void main(String args[]) { Producer producer = new Producer(); producer.start(); new Consumer(producer).start(); } }