Below are two pdf's which discuss and outline the Java Message Service, JMS, tutorial.

One Hour Java Messaging Service Tutorial
Advanced One Hour Java Messaging Service Tutorial

 

Planning on a little spring cleaning and getting rid of all those old electronics? With the way technology changes so quickly, it seems like we no sooner have one new electronic piece and there’s a new one on the market that we absolutely have to have. The result is a ton of used electronics stored away. Now it’s time to get rid of everything, here are some tips on what to do with all that old tech stuff and how to do it safely.

Save on Landfill Waste

Few people really realize where their electronics wind up when they throw them in the trash or dumpster. They assume they’re getting taken care of and just forget about them. According to the Environmental Protection Agency, one of the fastest growing components of landfill waste is electronics. The unfortunate part of this is that these electronics are filled with lead, mercury and other toxic chemicals – chemicals that find their way into our soil and water.

This results in the contamination of our lakes, streams and soil. The best way to avoid this is by knowing where your electronics are going and to dispose of them safely. Contact the recycling center in your area and ask for the best place to dispose of your old electronics.

Think of Security

Our lives are filled with electronic technology, whether it’s in the form of computers, tablets, smart phones or video games. Most of these electronics allow network sharing with people all over the world. With identity theft such a growing concern, much of our private lives and personal information is entered in the hard drives of these items.

Before you dispose of any electronics, make sure the hard drives are wiped clean of all personal information. This requires more than just “deleting” files. If you’re not sure how to correctly get rid of the information, contact a professional to do this for you. Even if you have to pay to have it done, it’s a minimal expense compared to having your private information stolen.

Find New Homes for Your Electronics

Once you’ve cleaned out your electronics of personal information, they may still be worth something to other individuals. You may know of a child or elderly person who would really appreciate a “new” computer or a tablet. Someone who has never owned a smart phone or laptop may be thrilled to suddenly own one, even if they are obsolete to you.

If you can’t find anyone that wants them, consider selling them on places like eBay, Craigslist or one of the many other online auction sites. The old saying, “one man’s junk is another man’s gold” is especially true when it comes to electronics. Many people like building computers using their own parts.

Students in computer-related programs also utilize used electronics as a form of hands-on training. Most schools also take in donated computers, televisions and cell phones. Contact your electric company or school district to get information on where you can take your old electronics. You’ll be not only cleaning out your house but also helping the environment.

Related:

Cloud Computing: What It Means and How It Could Threaten the Traditional Outsourcing Model

Python programming language is general purpose open source programming language. One of its main features is flexibility and ease of use. Python has a variety of useful set of utilities and libraries for data processing and analytical tasks. Currently due to the rise in demand of big data processing python has grown in popularity because its features are easy to use which are core to the processing of huge chunks of information.

Guido Van Rossum, the pioneer of python, introduced python in the year 1980 and then implemented it in 1989. The intention behind the development of python was to make it open source language that can also be used for commercial projects. The fundamental principle of python is to write the code that is easy to use, highly readable and embrace writing fewer lines of code for achieving a particular task. One of the most popular standard libraries which have ready to use tools for performing a various work is Python Package Index. It was introduced in January 2016 and contains more than 72,000 packages for third-party software usage.

Python plays a critical role in linking data to customers. Recently python has found few entry barriers and many people have had access to have experienced the power of python in the past. So, what makes python the best language for big data analytics?

One of the reasons to choose python is that python ecosystem is very vibrant, the ratings at Redmonk are a proof of the strength python community. The Redmonk ranking is based on StackOverflow discussions and contribution made in Github to determine the popularity of programming language on the method used by users to ask questions about Python and the number of the open source projects contributions.

The original article was posted by Michael Veksler on Quora

A very well known fact is that code is written once, but it is read many times. This means that a good developer, in any language, writes understandable code. Writing understandable code is not always easy, and takes practice. The difficult part, is that you read what you have just written and it makes perfect sense to you, but a year later you curse the idiot who wrote that code, without realizing it was you.

The best way to learn how to write readable code, is to collaborate with others. Other people will spot badly written code, faster than the author. There are plenty of open source projects, which you can start working on and learn from more experienced programmers.

Readability is a tricky thing, and involves several aspects:

1. Never surprise the reader of your code, even if it will be you a year from now. For example, don’t call a function max() when sometimes it returns the minimum().
2. Be consistent, and use the same conventions throughout your code. Not only the same naming conventions, and the same indentation, but also the same semantics. If, for example, most of your functions return a negative value for failure and a positive for success, then avoid writing functions that return false on failure.
3. Write short functions, so that they fit your screen. I hate strict rules, since there are always exceptions, but from my experience you can almost always write functions short enough to fit your screen. Throughout my carrier I had only a few cases when writing short function was either impossible, or resulted in much worse code.
4. Use descriptive names, unless this is one of those standard names, such as i or it in a loop. Don’t make the name too long, on one hand, but don’t make it cryptic on the other.
5. Define function names by what they do, not by what they are used for or how they are implemented. If you name functions by what they do, then code will be much more readable, and much more reusable.
6. Avoid global state as much as you can. Global variables, and sometimes attributes in an object, are difficult to reason about. It is difficult to understand why such global state changes, when it does, and requires a lot of debugging.
7. As Donald Knuth wrote in one of his papers: “Early optimization is the root of all evil”. Meaning, write for readability first, optimize later.
8. The opposite of the previous rule: if you have an alternative which has similar readability, but lower complexity, use it. Also, if you have a polynomial alternative to your exponential algorithm (when N > 10), you should use that.

Use standard library whenever it makes your code shorter; don’t implement everything yourself. External libraries are more problematic, and are both good and bad. With external libraries, such as boost, you can save a lot of work. You should really learn boost, with the added benefit that the c++ standard gets more and more form boost. The negative with boost is that it changes over time, and code that works today may break tomorrow. Also, if you try to combine a third-party library, which uses a specific version of boost, it may break with your current version of boost. This does not happen often, but it may.

Don’t blindly use C++ standard library without understanding what it does - learn it. You look at std::vector::push_back() documentation at it tells you that its complexity is O(1), amortized. What does that mean? How does it work? What are benefits and what are the costs? Same with std::map, and with std::unordered_map. Knowing the difference between these two maps, you’d know when to use each one of them.

Never call new or delete directly, use std::make_unique and [cost c++]std::make_shared[/code] instead. Try to implement usique_ptr, shared_ptr, weak_ptr yourself, in order to understand what they actually do. People do dumb things with these types, since they don’t understand what these pointers are.

Every time you look at a new class or function, in boost or in std, ask yourself “why is it done this way and not another?”. It will help you understand trade-offs in software development, and will help you use the right tool for your job. Don’t be afraid to peek into the source of boost and the std, and try to understand how it works. It will not be easy, at first, but you will learn a lot.

Know what complexity is, and how to calculate it. Avoid exponential and cubic complexity, unless you know your N is very low, and will always stay low.

Learn data-structures and algorithms, and know them. Many people think that it is simply a wasted time, since all data-structures are implemented in standard libraries, but this is not as simple as that. By understanding data-structures, you’d find it easier to pick the right library. Also, believe it or now, after 25 years since I learned data-structures, I still use this knowledge. Half a year ago I had to implemented a hash table, since I needed fast serialization capability which the available libraries did not provide. Now I am writing some sort of interval-btree, since using std::map, for the same purpose, turned up to be very very slow, and the performance bottleneck of my code.

Notice that you can’t just find interval-btree on Wikipedia, or stack-overflow. The closest thing you can find is Interval tree, but it has some performance drawbacks. So how can you implement an interval-btree, unless you know what a btree is and what an interval-tree is? I strongly suggest, again, that you learn and remember data-structures.

These are the most important things, which will make you a better programmer. The other things will follow.