For Java applications is difficult and expensive to achieve predictable, scalable performance. Simple switching from the single-server environments to multi-server can cause overall application throughput to collapse. Adding more data can cause the database to need progressively more resources. Java applications that work instantly in test, can be twenty times slower in response time when loaded with concurrent users.

The only (very complex) way to truly scale Java applications is to use three server tiers. The first is a HTTP-driven GUI, the second a Java server that de/serializes the tables of the third database tier into Java objects to perform the application logic. These tree tiers are often referred to as clustering, which is incorrect. Clustering is not related to vertically fragmenting the application but paralleling each server tier horizontally. So clustering can only be implemented independently for each of the tiers and requires very different functionality in each. In the case of the Web tier, no server-to-server communication is necessary, whereas at the other extreme, the database tier must manage transactional consistency across its cluster. This means that the cost of scalability is dramatically different for each of those tiers. Management and tuning is also completely different for each as well.

The HTTP tier performs SSL encryption and decryption duties, handles unique client connections by means of HTTP headers with ‘sticky load balancing’ information. HTTP requests are load-balanced across stateless servers and routed to designated J2EE server for processing. The application has to support sticky load balancing from the Web tier to be able to cluster both HTTP and Java tiers. Such Java applications exhibit intra-tier communication complexity that directly impairs scalable performance. The clustering of the database server has to be a function of the database product used, but it is impossible to scale the Java server without implementing some form of local data caching. Common forms are coherent clustered caching, fully replicated caching and partitioned caching.

Clustered caching maintains data in the Java application tier to satisfy data access requests from the cache without loading the database. The cache must not grow too large and provide data as current as necessary. Not all data is needed up-to-date. The cache expires data by LRU – least recently used and elapsed time algorithms.  In clustered systems, servers notify each other about data modifications and either delete or refresh the outdated data page. Coherent clustered caching needs the same as application logic to synchronize cache pages to guarantee a thread-safe implementation. A kind of dual-phase commit on page changes is required in a distributed cache to maintain transactional data consistency.

A fully replicated cache however does not have the problems of clustered caching but shares modifications with other members of the cluster in a “push” model.  While the data access has no measurable latency, a transaction should only be closed when the data from the cache has been serialized to the database tier. This is however mostly done in lazy writes and thus risky. The other problem is related to data locking because theoretically two servers can access the same data to write at the same time and therefore cause conflicts at transaction close.

The solution is the partitioned cache where each cluster server owns one unique fragment of the complete data set. All data are cached to the other servers but writes have to be synchronized to the owning server, but because communication is any-to-any, partitioned caches scale linearly with number of requests and data volume as you add servers. Replicating data from the owner and de-serializing tables into objects adds substantial latency. Therefore the application servers typically ‘object-cache the database-cache’ to avoid the additional de-serialization overhead for multiple object requests. The cache can load many objects from a single cache page in one I/O request rather than reading multiple table entries.

However, a substantially growing number of applications no longer read data from a database. Particularly process oriented applications (and that should be all of them) require data synchronization via backend interfaces such as SOA or MQ series from application silos. More often than not such interfaces require stateful conversations. Compared to database access, Web services based communications are at least a magnitude worse in performance, response time and throughput. Much of that has to do with the problems of XML defined data structures, the weak, ambiguous, and non-canonical XSD-based data definitions and the resultant parsing and validation. To reduce the number of transfers, SOA requests often pass a lot of incidental data because it might be needed, to avoid multiple data accesses. Obviously that is similar to creating a kind of SOA cache, but without any of the above mentioned mechanisms of data concurrency. Web services provided data are in principle always out of date. Web services transactions are so slow that they can not be used for applications that involve user interactions but just for straight-through processes without user intervention. To implement clustered caching for SOA Web services creates substantial problems, mostly because there is no defined mechanism for push-updates and lazy database writes. All of it has to be manually implemented by the Java programmers and is mostly hard-coded and application specific.

The complexity of measuring and predicting hardware and software performance becomes therefore a very complex task. During my years in IBM one of the key elements of designing a well working mainframe environment was based on the balanced system approach. The right mix of CPU power, RAM, disk I/Os was needed to get the most bang for your buck. Today the need for network bandwidth for the various intricacies of each of the tiers becomes the key element while HW is looked at as a cheap commodity. The immense OVERHEAD involved in juggling Web/HTTP clusters, Java tier clusters and expensive High-Availability clusters for the database tier requires huge amounts of commodity HW that is mostly not balanced to achieve scalable applications. Most systems just provide enough of everything to work. The idea of Cloud computing has to do with providing virtualized resources to such tiered systems adding more overhead for the virtualization. Hm, it sounds not very professional and well thought out to me …

CONCLUSION: Could the substantial overhead in using sticky-load-balancing, transaction-safe Java caching and database clustering, plus the substantial overhead for parsing and validating the XML data for SOA not be avoided? All of the above have been reasons why I chose a different route for the Papyrus Platform. Rather than the immense complexity of multi-layered caches – with multiple conversion from tables to cache pages to objects and reverse – I decided to collapse the horizontal structures and work with a purely (vertical) object model from definition to storage. That enables the use of the meta-data repository for application life-cycle management and substantially simplifies systems management and tuning.

The proxy replication mechanism of the object-relational database of the Papyrus Platform uses a partitioned caching concept where there is always a unique data owner and each server node uses a replicated copy that is either pull or push updated as per proxy definition. The objects do not have to be de/serialized as they are cached/replicated/binary stored as is. The same mechanism works transparently for all objects that are populated via Web services or other backend interfaces. The drawback is that during testing or at low load it seems to be not as fast as a Java app, but in difference it does scale linearly without needing additional programming or software as you add more commodity HW. Papyrus uses the same concepts across all servers because there are no tiers necessary and it also does not need virtualization.

Where To Get Cool Games For The SciPhone I68: As I alluded to earlier, Java is where it is at. The earliest clones did not have this feature. If you google or search “get jar” into any major search engine, you’ll see sites where you can download Java games for free.

On the top of the main page, click on “software.” Then, on the left hand side of the site (toward the bottom) is a games icon. If you click it, you’ll be given the most popular downloads first. But if you have an idea as to what type of game you want, they have it broken down into genres like action, adventure, sports, etc, which can make things easier and quicker.

Once you find the game or games you want to download, click on it. Most games will just give you the jar files in the download box. Some will ask for your device though. In this case, you’ll enter the only CECT option, which is the A100 (works on all models.) Sometimes, this option isn’t given (rarely). In this case, many of the Nokia options will work, particularly the 2610.

Downloading Java Games On Your SciPhone I68 JAVA : Once you’re at this step, you’ll need to get the game onto your phone. You can do this in two ways – via your PC or through the phone’s web browser. (Obviously, you’ll have to have your WAP browser set up properly for your carrier.) Note that opera mini usually will not allow downloads, so you’ll have to use the WAP browser. But, the game will give you the exact link or code so that you can easily get to it from the “go to” icon on the browser. Once you type in the html address and code, you’ll simply hit “download.”

Alternatively, you can download the game via USB port. This is how I prefer to do it because it saves me data time and money and also, I like to have a copy on my computer in case it should accidentally be deleted. For this, hook the USB up to both your computer and phone. Hit “mass storage” on the phone. Then hit the jar file / game you want and scroll to “save as.” Then, find your device in the “save in” folder . This will usually be the bottom option. (For me, it’s often the K drive.) Once you’ve chosen this, hit save.

Then, unplug the phone from the USB. Go into the documents icon of the phone. Go into “memory card.” Go into “received.” (If you don’t have a received file, go into whatever file you saved the jar game into.) You will see the name of the game listed. Click it. You will be given a list of options. The first is “install.” Click install. The phone will install the game and you are almost done.

The final step is to play the game. For this hit your Java icon. Then click “installed java software.” At the bottom of the list, you’ll see your game listed. Click it and then hit launch. That’s really it. (The process for getting to and playing the game is the same no matter how you installed it.)

Incidentally, the same process goes for any Java download including software, productivity, and browsers like Opera Mini, etc.

Java island is mountainous with numerous active volcanoes. The climate is muggy year-round, often punctuated by monsoon rains. Along with the fertile soil that surround the volcanic areas, the early Dutch settlers found these conditions to be very conducive to growing coffee.

Arabica was introduced to Indonesia in the 17th century and this was planted vigorously by the Dutch colonial government. The Arabica was eventually wiped out for the most part by a plague known as coffee rust although coffee plants in other regions were not affected. Robusta was the logical alternative because of its resistance to diseases.

Later on in the early 20th century, the colonial government would build the infrastructure to confine the growth of coffee to East and Central Java. East Java would produce Arabica simply because of their more mountainous regions while Central Java primarily produced Robusta.

Today Indonesia is the biggest producer of coffee in Southeast Asia and third in the world. The coffees they export are from both the Arabica and Robusta stocks although gourmet coffee makes up only about ten percent of their export. This is due mainly to the roles that the plague along with World War II and internal political strife have played in forming the Indonesian coffee industry.

Arabica from Indonesia are primarily from the islands of Java, Sumatra and Sulawesi. Sumatra is also mountainous with active volcanoes. The highlands to the north and west of Sumatra produces very high quality Arabica beans. Sulawesi coffee is similar in character and appearance to the Sumatran.

Even though Java is the most well-known of Indonesian coffee exports, many experts agree that Sumatra coffee is the best of the lot owing to a fruity and syrupy taste. It is unclear why coffee drinkers today have equated the word java with coffee itself. One story tells us that because coffee from Java was so popular at the time, merchants would brand their coffee with that name in order to capitalize on its popularity as well as increase sales. As you can see, brand marketing was very much alive in the 18th century.

And because brand marketing is often mischievous and creates a lot of unnecessary hype. As a result, buying a bag of coffee can suddenly be confusing especially when the word “Java” is present in the packaging. Are you actually buying coffee of the gourmet variety from the island of Java or just some plain coffee using the term just to make it a more attractive, not to mention expensive, commodity? Adding to the mess, when looking up the word itself on the search engines can take you to pages of undecipherable computer programming language when all you wanted was a hot cup.

That being said, when looking specifically for Indonesian coffee, the most common is Java Estate. But if you want a treat, look beyond Java and let your taste buds feast on Sumatra Mandehling instead. It is sure to erase any confusion.

Sun Microsystems offers many certifications starting from programmer level to architect level. The latest version of programmer (SCJP) exam is SCJP 5.0 – Sun Certified Programmer for the Java 2 Platform, Standard Edition 5.0 (CX-310-055). Sun started calling SCJP 5.0 instead SCJP 1.5 from this new version.

Achieving this certification provides clear evidence that a programmer understands the basic syntax and structure of the Java programming language based on new syntax introduced in SCJP 5.0. The certified programmer can create Java technology applications that run on server and desktop systems using J2SE 5.0 ( Java Tiger). Java Tiger is the another name of J2SE 5.0.

NOTE: The external version number of this release is 5.0 and its internal version number is 1.5.0.

What is new in Java Tiger ?

Changes include generic types, metadata, autoboxing, an enhanced for loop, enumerated types, static import, C style formatted input/output, variable arguments, concurrency utilities, and simpler RMI interface generation.

Wow ! Thanks to Sun Microsystems for providing such a valuable features for Java Programmers.

So, if you decided to take Sun Java Programmer certification (SCJP) go ahead with SCJP 5.0 and be a Java Tiger Certified Programmer and enjoy the benefits of new features.

Changes in Exam Objectives from SCJP 1.4 to SCJP 5.0

SCJP 1.4

SCJP 5.0

Section 1: Declarations and Access Control

Section 2: Flow control, Assertions, and Exception Handling

Section 3: Garbage Collection

Section 4: Language Fundamentals

Section 5: Operators and Assignments

Section 6: Overloading, Overriding, Runtime Type and Object Orientation

Section 7: Threads

Section 8: Fundamental Classes in the java.lang Package

Section 9: The Collections Framework

Section 1: Declarations, Initialization and Scoping

Section 2: Flow Control

Section 3: API Contents

Section 4: Concurrency

Section 5: OO Concepts

Section 6: Collections / Generics

Section 7: Fundamentals

Is SCJP 5.0 easy compared to SCJP 1.4 as it has limited number of sections? No, most of the concepts are new in SCJP 5.0. Some of them are not related with SCJP 1.4.

SCJP 5.0 Exam Details

Delivered at: Authorized Worldwide Prometric Testing Centers

Prerequisites: None

Other exams/assignments required for this certification: None

Exam type: Multiple choice and drag and drop

Number of questions: 72

Pass score: 59% (43 of 72 questions)

Time limit: 175 minutes

After completion of SCJP 5.0 exam you are familiar with Java Tiger concepts like generic types, metadata, auto boxing, an enhanced for loop, enumerated types, static import, variable arguments, etc.

How long I need to prepare for this exam?

The answer is it depends on your current knowledge in Java programming and OO Concepts. You may get an approximate estimation from EPractize Labs SCJP 5.0 Preparation Time Calculator.

How to start? Where to start?

First go to Sun’s website and understand the exam objectives. http://www.sun.com/training/catalog/courses/CX-310-055.xml

Plan for your preparation. If needed calculate an estimation from EPractize Labs SCJP 5.0 Preparation Time Calculator.

Identify your weak areas based on the exam objectives. Set more focus on those topics.

Study and workout the program examples.

Practice with mock exams and see where you are. Continue your practice till you achieve your goal.

Achieve your SCJP 5.0 certificate and share your success WITH YOUR FRIENDS AND COLLEAGUES!

Recommended SCJP 5.0 Exam Preparation Kit

Use SCJP 5.0 Exam EPractize Labs – Personal Edition for empowering your preparation by PPA-1(Plan, Practize, Achieve) methodology.

SCJP 5.0 Certification Benefits

For the Individual

Clear evidence that you are a Java Tiger programmer.

The certification empowers in driving Java Programming based on J2SE 5.0.

SCJP 5.0 certified programmers can easily design and develop the code based on J2SE 5.0.

Being a SCJP 5.0 certified programmer helps you to improve your career potential, gain more respect, boost up your job security and opportunities.

With SCJP 5.0 certified programmer, you become more competitive in the job market.

For the organization

Enables management to distinguish SCJP 5.0 certified programmer as Java professionals who can develop quality code efficiently and effectively.

Helps in deciding the best development APIs or Java Components based on latest J2SE APIs.

More confidence to work on Java Code technical decisions with business partners.

Enables project team to get best coding practices and guidance from a qualified Java Programmer.

Good Luck !

Called “BETACache,” the new technology resulted from BETA’s PHP developers Rock Mutchler, Paul-Anton van Handel, Jon Bauer, Bernhard Schenkenfelder, and Eric Hollander.

“These guys may have devised the ultimate scalability breakthrough for large-scale communities around the world – it’s like taking the performance of a Volkswagen and turning it into a Bentley overnight,” says Chris Honetschlaeger, BETA Records president. “From Facebook down to the world’s 20 million PHP websites, we at BETA are hopeful to finally give back to the PHP community we so admire.”

PHP applications require a means of caching data from remote services, expensive database queries and other performance-killing operations. These problems are greatly magnified by Web 2.0′s heavy reliance on numerous AJAX requests to the web application, and frequent web service calls to partners.

“BETACache could offer a superior alternative to the widely-used memcached, as well as opening up a tremendous amount of other features to PHP application engineers through JCS,” says Rock Mutchler, BETA VP of Technology. “With the BETACache process in place, we can now use the leading technologies to solve the performance issues that developers face. At BETA we have modified Zend Cache in the Zend Framework, by adding our own custom object that makes use of the Zend Platform Java Bridge.”

The Zend Platform PHP/Java Bridge is a PHP module which provides stable and high-performance access to a Java Virtual Machine. “Through this we’re able to use the JCS package to provide an enterprise-class, pluggable and tunable distributed caching system written in Java,” Mutchler states.

BETACache offers a clustered, distributed cache system which automatically caches objects in local memory, local disk, or on remote servers. The Zend Java Bridge allows high-performance enterprise-class integration between the PHP environment and JCS. “We are excited about future enhancements of BETACache to leverage Enterprise Java persistence systems in our clustered PHP application,” Hollander said.

Java is a revolutionary language and so, for this reason, it is the most accepted computing language in use today for a wide-ranging purpose. Some of the substantial benefits of Java Programming language are:

Hence for these considerable benefits, Java is chosen as the programming language for the network computers (NC) and has been perceived as a universal front end for the enterprise database.