Web Development Tools
Bunyan is a NodeJS library that rethinks logging in some really useful ways. I wrote a Java port you can use in your applications.
In particular, with Bunyan, logs are JSON - and Bunyan comes with a great filtering and analysis tool.
The Java port uses some innovative techniques to make logging simple and foolproof - in particular, a use of AutoCloseable to make a logging code simple and...
on Jan 18, 2015
Using the Java 8 Date Time Classes with JPA!
With the Java 8 SE release, developers get a splendid new best-in-class Date-Time API. Wouldn't it be nice if you could use it with JPA? Not so fast. JPA and for that matter JDBC know nothing about the new classes, and if you use them in your entities, JPA will map them to BLOBs in your database by default. This happens in DDL or database creation, in...
on Jun 17, 2014
If you are having a problem with your JPA queries and you are trying to understand what SQL queries it actually sends below the covers you can configure the JPA runtime to show the actual SQL statements it sends over. How? Well for EclipseLink you would add the following to your persistence.xml file.
<property name="eclipselink.logging.level" value="FINEST"/>...
on Oct 27, 2013
Server-Sent Events (SSE) is part of HTML5. SSE is a simple, undirectional communication from server to browser. It allows server to push data to client once a connection is established. The entire point of SSE is to make it easy for the server to push messages to the browser, once the browser has first established a connection to the server. These messages are of the form "field: value" with...
on May 21, 2014
javax.servlet.http.HttpSession provides a way to identify an user across multiple HTTP requests and to store user specified information. In other words, it provides a support of stateful communications with the stateless HTTP protocol.
For security and memory management, sessions need to be invalidated at a certain time. There are two related methods in HttpSession.
on Aug 29, 2013
JSR 356: Java API for WebSocket provides a standard Java API for creating WebSocket Applications. The specification provides an API for...
on Aug 7, 2013
Expression Language (EL) was first introduced as part of JSTL 1.0, was then moved JSP 2.0 and was unified with JSF 1.2 in JSP 2.1. In Java EE 7, EL is a new separate JSR, JSR 341. Many new features are introduced in EL 3.0.
This blog shows how to use new following new features of EL 3.0:
Lambda expression (section 1.20 of EL 3.0 spec)
The new operator ; to separate...
on Jul 1, 2013
Asynchronous operation was introduced in Servlet 3.0. ServletRequest#startAsync is used to put the request into asynchronous mode. A thread need to be created implicitly or explicitly (see here for an example).
Servlet 3.1, JSR 340 includes clarifications in asynchronous area. Besides Servlet 3,1, Concurreny Utilities for Java EE 1.0, JSR 236 is introduced in Java EE 7. JSR 236 provides a...
on Jun 6, 2013
Update: In Servlet 3.0, the behavior of using response is undefined after invoking #complete or #dispatch. In Servlet 3.1, it is clarified that AsyncContext#getResponse will throw IllegalStateException. The blog has been updated for this.
Asynchronous operation is supported in Servlet 3.0. I have discussed startAsync in my previous blog, startAsync in Servlet 3.0. In this blog, I will discuss...
on May 14, 2013
Update: Invoke WebConnection#close when there is an error.
Servlet 3.1 Specification (JSR 340) is almost ready for the release. One of the new features is the support for protocol upgrade.
HTTP protocol upgrade was introduced in HTTP 1.1 (RFC 2616):
The Upgrade general-header allows the client to specify what additional communication protocols it supports and would like to use if the server...
on May 7, 2013
JavaEE 7 and Glassfish 4.0 were released a little while ago.
What is in the future? Well, see the Aquarium blog for the latest Glassfish Roadmap.
And that is it.
on Nov 4, 2013
See the release notes for what was fixed. If you want to download it, see this page for more information.
on Oct 31, 2013
#How to run the dev test cases
All of the test cases can't be ran on the windows platform because the firefox can't support the ajax and JSF based on the windows platform very well. If you want to ran the tests, please check out all of the codes to the linux, ubuntu or mac platform.
1). Download the firefox and install it, On my platform, I...
on Oct 14, 2013
At the JavaOne 2013 Java Technical Keynote, there was a series of demos of software that enables two people to play chess, using some of Java's latest features, including Java EE 7 Websockets, many variations of Java 8 (recent weekly builds), Lambda Expressions, Java ME, Embedded Java, ... It was an impressive demo of many of Java's recently-released and not-yet-finally-released capabilities,...
on Sep 23, 2013
Web Services and XML
Backbone.js gives structure to web applications by providing models with key-value binding and custom events, collections with a rich API of enumerable functions, views with declarative event handling, and connects it all to your existing API over a RESTful JSON interface. JAX-RS provides a standardized API for building RESTful web services in Java. This example will show how to...
on Sep 16, 2013
Java API for WebSocket is a new JSR to Java EE 7. It provides a stardard Java API for creating WebSocket applications. This gives web applications the ability to push data.
In Java EE 6 samples, we added a chat room sample to illustrate how to use of Servlet 3.0 asynchronous operation. In that sample, the servlet code did the following:
keep track of AsyncContext in a Queue
create a thread to...
on Aug 13, 2013
Servlet 3.1 Specification (JSR 340) and Java Authorization Contract for Containers (JSR 115) MR3 are almost ready for release. Besides "*", the role-name "**" is introduced in the above two specifications.
In a nutshell, "*" means any role defined in web.xml and "**" means any authenticated user.
Prior to Servlet 3.1, web containers use proprietary mechanisms to add security-constraints for any...
on Apr 19, 2013
Servlet 3.1 Specification (JSR 340) is almost ready for the release. Several new security features have been added in this version of Servlet specification.
In this blog, I will explain one of the security features, namely deny-uncovered-http-methods.
Let us take a look at a simple security-constraint in web.xml as follows:
<web-app xmlns="http://www.w3.org/2001/XMLSchema" ...
on Apr 19, 2013
Servlet 3.1 was in Public Review in Janurary 2013. And it is in Proposed Final Draft now. Most of the new features are related to security.
In this following, I will highlight features since Servlet 3.1 Public Review:
add new API javax.servlet.http.Part#getSubmittedFileName
add new API javax.servlet.ServletContext#getVirtualServerNameThis API allows a JASPIC module to be registered in a Servlet...
on Mar 18, 2013
Update: One should not use response in AsyncListener#onComplete. Only print debug in this example.
Servlet 3.1 (JSR 340) is almost ready for the release. One of the new features is the support for non-blocking IO. ReadListener and WriteListener are introduced to allow non-blocking processing in Servlet.
Non-blocking IO can only be used in async (defined in Servlet 3.0) or the upgrade mode. We can...
on Apr 16, 2013