In the normal course of solving a general programming problem, it is almost certain that you will become compelled to create, and identify useful ways by which to hold any number of objects within your program. In Java, you are normally inclined toward the array as the natural choice for holding a group of primitives, but this has the obvious limitation of being of a fixed size, whereas, under...
on Feb 12, 2014
Interfaces are completely abstract classes in Java that provide you with a uniform way to properly delineate the structure or inner workings of your program from its publicly available interface, with the consequence being a greater amount of flexibility and reusable code as well as more control over how you create and interact with other classes. More precisely, they are a special construct in...
on Jan 18, 2014
In object oriented programming, polymorphism is a feature that allows you to provide a single interface to varying entities of the same type. This is analogous to the interpretation of the same concept in the field of Biology.
To understand how this works in Java, we must consider inheritance and the ways by which the Java programming language makes method calls.
When you create a class in Java...
on Jan 7, 2014
There are mainly two ways by which one may reuse classes in Java. The first is by way of composition. Composition provides a way to compose your classes from objects of existing classes, essentially making use of the objects' functionality as opposed to its form.
The second method is by what we call inheritance, which describes how one may derive a new class as a type of an existing class. With...
on Dec 18, 2013
A key consideration for the library designer in the normal conduct of operations is maintaining the ability to make changes or improvements to the library at any time without requiring the consumers (client programmers) of that library to do the same. In Java, a library consists of a logical grouping of .class files packaged together to make a working program.
An apt analogy to this point may be...
on Dec 8, 2013
What is Java?
Java is an high-level programming language created by James Gosling from Sun Microsystems on 1991, released on 1995. Nowadays, Oracle Corporation has the steermanship for Java. Its license is GNU General Public License (GPL).
Is executed on more than 850 millions of devices on all over the world. Java applications are compiled to bytecode that can run on any Java Virtual Machine (...
on Jan 30, 2014
Introduction to Class Diagram
In any project's planning phase, the programmer should describe the behaviour of the different objects that are required to satisfy business use cases. However objects can't emerge from nothing, so you need a template that describe the type of objects that the system will have. As a result, you will need to show a diagram with all the classes involved and their...
on Jan 22, 2014
Why do we need to program?
Technology is part of our life. The world is changing daily and everything is getting automated. Learn to program is the creative way we can take our ideas to the next level and express solutions to society. By designing programs, we learn several abilities like critical reading, analytical thinking and create synthesis. The programmer defines the problem, plans a...
on Jan 21, 2014
The Java is a platform which grown up quickly, for many rations such it can write once time and run anywhere, it runs languages on JVM. There is a myth that Java cannot compile its sources on run time, but it's truth?
Have a dynamic language is important to make some projects, for example, calculate taxes to different cities, so the source should be on the database and each city it puts the...
on Jan 19, 2014
HTML Online Editor Sample
I have been contemplating for a number of months about reviewing a cache of articles and videos on topics like Performance tuning, JVM, GC in Java, Mechanical Sympathy, etc... and finally took the time to do it - may be this was the point in my intellectual progress when was I required to do such a thing!
Thanks to Attila-Mihaly for giving me the...
on Jan 17, 2014
This is my first blog on java.net! Happy new year!
At 2014/01/11, A big Java EE 7 event has been held on China Nanjing Software Valley jointly organized by China (Nanjing) Software Valley Joint Management Committee and China Nanjing Java User Group.
ChinaNanjingJUG(http://q.weibo.com/1696581) is founded at 2013, and focus on the promotion of Java EE and Java related technology into China....
on Jan 13, 2014
Real-World Machine Learning , Storm Applied, and Git in Practice -- MEAP updates + 45% savings. Use Promotional Code 012914jn at manning.com and Save 45% on these eBooks today!
Real-World Machine Learning by Henrik Brink and Joseph W. Richards has been updated Chapter 1 and 2 and added Chapter 3.
Chapter 3 covers the basics required to understand machine learning modeling. It focuses on the big-...
on Jan 29, 2014
Groovy Weather: POGOs, Gson, and Open Weather" by Ken Kousen of Making Java Groovy is 45% off with promotional code kousenjn at manning.com.
The Open Weather Map web site provides weather information as a RESTful web service in JSON form. In this blog post, I show how to access the site using Groovy and convert the results into Groovy classes using Gson, the JSON parser from Google. The code...
on Jan 7, 2014
The columnar storage is good, especially when there are lots of tabular fields (this is quite common). In querying, the data to traverse is far less than that on the row storage. Less data to traverse brings less I/O workloads and higher query speed. However, the Hadoop application consumes most time on the hard disk I/O without columnar storage.
Both Hive and Impala support columnar storage, but...
on Jan 24, 2014
The data warehouse is essential to enterprise business intelligence, which accounts for a great part of the total enterprise cost. With the global data explosion in recent years, the business data volume grow significantly, posing a serious challenge for enterprise data warehouse to meet the diverse and complex business demands. More data, more data warehouse applications, more concurrent...
on Dec 11, 2013
Every once in a while I run into someone that has a JVM that is running back to back collections and yet the heap is still almost full after each attempt! When they discover that their problem is related to the JVM not having enough memory they often ask the question, why didn't the JVM throw an OutOfMemoryError? After all my application is not making any forward progress and the reason is Java...
on Jan 8, 2014
Lets start with a small quiz: Can you find 3 differences in the pictures below?
Yeah, you got it. That was an easy one. :)
Surprisingly, implementing preview for extra asset types has been relatively simple as well. When coming up with the architecture of DAM, the Magnolia team chose to not generate previews and thumbnails of assets directly in the module, but rather delegate this functionality...
on Dec 31, 2013
One day I found myself in the situation that I had to write a unit test which checks whether my code is annotated in a particular way. I wondered how one could do that without doing an integration test that actually processes that annotations. My first idea was to use the Reflection API, which in fact worked, but was not looking smart. In fact, I wanted to have a Hamcrest matcher instead, since...
on Dec 27, 2013
Just recently I was engaged to assist with an application that wasn’t behaving. The application, running in a 1.7.0_45 JVM, relied heavily on a 3rd party SAAS framework. That vendor provided my client with a list of 26 different JVM flags that should be set. When faced with this long list of flags I couldn’t resist asking why all the flags and why these flags. After all there are more than 700...
on Dec 11, 2013
I was very pleased to see the JFrog team take me up on my suggestion early this year that "Maybe the JFrog team will consider giving a presentation on how they put all this together at JavaOne this September". Unfortunately for me, the session (Building a Massively Scalable Cloud Service from the Ground Up) was already filled to capacity as I walked up to the door, so I was unable to attend....
on Dec 8, 2013