Monday Jul 16, 2012

Introducing Groovy

Oracle developer Jim Driscoll has a new article up on otn/java, titled “Introducing Groovy,” that shows readers how to master the basics of Groovy, a general-purpose scripting language that runs on the Java Virtual Machine (JVM) – and, as Driscoll emphasizes -- one that can largely be viewed as a superset of Java.

He presents a “Hello World” program that can be understood as either a Java or Groovy program and will compile and run in either environment. Driscoll takes readers through the intricate connections and disconnects between Java and Groovy. For example, Groovy is public by default and “Groovy deals with String objects using double quotation marks with strings” which “allows for variable substitution”. And, “there are also strings with single quotation marks.”

Driscoll illustrates his points with copious code that illustrates how Java developers can tweak their own knowledge of Java to take advantage of Groovy’s strengths, so that, by the end of the article, the (Java-informed) reader more or less understands Groovy.

Check out the article here.

Wednesday Dec 21, 2011

Updating Java ME Applications

A new article up on otn/java, by Java ME expert Vikram Goyal, titled “Updating Java ME Applications,” demonstrates how easy it is to update the text, images, and source code for Java ME applications. Goyal explains that updating a Java ME application includes updating static data, such as text and images, as well as code components of the application. In the article, he develops a sample app that illustrates how to update an application.

As Goyal explains, “The article starts with the basics—updating simple text strings—and then moves to updating images. Finally, the article shows the easiest way to update the core application files, which Java ME makes quite easy. However, this ease can come at a price in terms of extra network traffic.”

Goyal concludes the article with some basic advice:

“If you don’t need to update the entire source code for your application, use the connection classes provided within the package, such as ContentConnection and HttpConnection, to update static data, such as text and images.

On the other hand, if you need to provide a mechanism for updating the entire source code, make sure you follow a valid update process on the server, and use platformRequest(String) with a URL that ends in jad to provide the updates. The device’s interface will then make sure the updates are applied by removing the old MIDlet and installing the new updated version.”

Read the complete article here.

Tuesday Oct 18, 2011

The Heads and Tails of Project Coin

JavaOne 2011 - Joseph Darcy, Member of the Oracle Technical Staff, spoke to a very large,
packed conference room in his “The Heads and Tails of Project Coin” (22641) session Tuesday.
Project Coin, a central part of Java 7, was described by Darcy as “a suite of language and
library changes to make things programmers do everyday easier.”

Project Coin makes life easier by removing extra text to make programs more readable;  
encouraging the writing of programs that are more reliable; and by integrating well with past and future changes.
Darcy emphasized that these are small language changes related to specification, implementation and testing;
there are no JVM changes. Project Coin was written to coordinate with forthcoming larger language changes.

Project Coin has strong IDE support:
• IntelliJ IDEA 10.5 and later                                                                                                
• Eclipse 3.7.1 and later                                                                                                                  
• NetBeans 7.0 and later

The six Project Coin features are:  
• Binary literals and underscores in literals                                                                                
• Strings in switch                                                                                                                          
• Diamond                                                                                                                                     
• Multi-catch and more precise rethrow                                                                                
• try-with-resources                                                                                                               
• Varargs warnings

Diamond and varargs warnings enable easier-to-use generics. Multi-catch and try-with-resources allow for more concise error handling. Strings-in-switch and literal improvements result in greater consistency and clarity.

Darcy proceeded to demonstrate five of the six Project Coin features to a highly engaged audience.
Check out his session slides and you can also view this talk @

What’s ahead for Project Coin in Java 8? Look for very small language changes on the horizon.

Wednesday Sep 14, 2011

Working with Java SE 7 Exception Changes

A new article by systems architect Manfred Riem, now up on otn/java, titled “Working with Java SE 7 Exception Changes,” covers important developments in Java 7’s Project Coin, focusing on exception handling -- specifically multi-catch, rethrow, and try-with-resources. Project Coin consists of the following small language changes, which are intended to simplify common programming tasks: strings in switch statements; better integral literals; multi-catch exceptions; improved type inference for generic instance creation; try-with-resources; and simplified varargs method invocation.

From the article itself:

“The exception handling changes in Java SE 7 allow you not only to program more concisely, as demonstrated in the multi-catch examples, but they also allow you to partially handle an exception and then let it bubble up, as covered in the re-throw examples. Java SE 7 also facilitates less error-prone exception cleanup…”

Read the complete article here.


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