Programming 1. 01 5 Basic Concepts of Programming. First off, Id like to say that Im writing these preliminary posts in a way that Ill assume you have very little knowledge in programming. Chapter 3 Operators, Expressions, and Program Flow The focus of this chapter is an indepth look at each of the ways that we can evaluate code, and write. Without using modulus and division operators The above two programs will check number is even or odd and displays result. Now we need to write a program to check. Java options pass in commandline arguments and feed user input to stdin. Excellent question In Java, the programming language wants to know what kind of information you are going to be storing in a variable. This is because Java is a. Java is PassbyValue, Dammit Introduction. I finally decided to write up a little something about Javas parameter passing. Im really tired of hearing folks. I want this content to provide anyone walking in off the street the knowledge to be able to write their first program with the Java programming language with as little pain as possible. So, lets get started with our first topic The 5 basic concepts of any programming language. This C Program which converts decimal to binary value. The program takes a number as the input and prints out the binary form of the number using a recursive. Java Operators. An operator is a symbol that operates on one or more arguments to produce a result. The Hello World program is so simple it doesnt use any operators. CodingBat code practice Code Help and Videos Java If and Boolean Logic. See also Java If Boolean Example Solution Code 1 video Java If Boolean Example Solution. You might say, Why are we talking about any programming language I thought this was about Java. Well, Ive found that its important to remember that a lot of programming languages are very similar, and knowing whats common between all programming languages will help you transition into any other programming language if you need to For example, with the Java programming knowledge I had obtained, it took me less than a month to learn how to program in a language called Objective C which is used for i. Phone apps.  Thats powerful stuff Before we start learning if youre someone who also enjoys learning by watching videos, then I have the perfect deal for you. You can get access to over 5. Simple Division Program In Java' title='Simple Division Program In Java' />Facebook community of like minded programmers for free for 3. You can click here to learn more about the Java courses. So here are the 5 basic concepts of any programming language Variables. Control Structures. Data Structures. Syntax. Tools. I recognize that these words probably look foreign to you, but dont worry, Ill do my very best at taking the mystery out of them. Now, theres a lot to say about each of these 5 concepts, so for todays post Ill only be talked about item 1, variables What is a variable Variables are the backbone of any program, and thus the backbone of any programming language. I like to start off by defining what were about to learn, so, Wiki defines a variable as follows Okay, well, thats kind of cryptic. To me, a variable is simply a way to store some sort of information for later use, and we can retrieve this information by referring to a word that will describe this information. For example, lets say you come to my website www. I want to do, is ask you what your name is so that I can greet you in a nice way the next time you visit my website. I would put a little text box on the screen that asks you what your name is that text box would represent a variable Lets say I called that text box your. Name, that would be the symbolic name or word for your variable as described from our wiki definition above. So now, when you type your name into the text box, that information would be stored in a variable called your. Name.  I would then be able to come back and say What value does the variable your. Name contain, and the program would tell me whatever it was your typed into that text box. This concept is extremely powerful in programming and is used constantly. It is what makes Facebook and Twitter work, its what makes paying your bills via your online bank work, its what allows you to place a bid on e. Bay.  Variables make the programming world go round. Now, if we want to get more specific, when it comes to the Java programming language, variables have different types. Gaming Websites more. Brace yourself here, as Im going to try to confuse you by explaining an important concept in three sentences. If I were to be storing your name in a variable, that type would be a String. Or, lets say I also wanted to store your age, that type would be stored as an Integer. Or lets say I wanted to store how much money you make in a year, that type would be stored as a Double. What the heck are String, Integer and Double Excellent question In Java, the programming language wants to know what kind of information you are going to be storing in a variable. This is because Java is a strongly typed language. I could teach you about what the difference is between a strongly typed language and a weakly typed language, but that will likely bore you right now, so lets just focus on what a type is in Java and why its important. Typing in Java, allows the programming language to know with absolute certainty that the information being stored in a variable will be a certain way. So like I said, if youre storing your age, you would use the Integer type well thats because in Java, an Integer means you have a number that wont have any decimal places in it. It will be a whole number, like 5, or 2. All of those numbers would be considered an Integer in Java. So what would happen if you tried to store something that wasnt an Integer, into an Integer variable, say for instance the value 3. Well, quite simply, you would get an error in the program and you would have to fix it In Java, when you specify that a variable is of type Integer, you are simply not allowed to store anything except a whole number. Specifying what kind of data that you are dealing with allows the programming language to use that data in interesting ways. Again, what I say specifying what kind of data, Im just referring to the type of data. Lets dive into the power of assigning a type to your data. What can you do with data types Lets start with a simple example. Your desire is to add two numbers together, lets say the number 2. Java will behave differently depending on the type of the variable thats storing this data. Let me show you what I mean If you have defined your variables to be of type Integer, then adding 2. Integer 2. 5. Makes perfect sense rightOf course, this is simple Math. But what happens if your variables are not Integers, but are StringsA String in Java is a different kind of data type and it behaves differently BECAUSE it is a different type of data. When we refer to a String in Java and in many other programming languages we are treating the data like its just a plain old sentence in the English language. A String just represents words or more specifically letters all placed in a certain order. Thats all the English language or any language is, a series of charactersletters placed in a certain order to give meaning to what youre writing down. So now I ask you, what does it mean to add two sentences togetherWhat does it mean to add two Strings together Ill show you. If you were to have two variables, each defined as Strings and they stored the data 2. We would get the String 2. This might be confusing at first, but it makes more sense when we use less misleading data. Lets assume that in our two String variables, we arent storing numbers, were storing words. So in variable 1 we store the String Hello, and in variable 2 we store the String World. Now what happens in your mind if I tell you to add those two words togetherHopefully your natural instinct is to say that the resulting String would be Hello World Thats all thats happening with the Strings 2. Java behaves differently because of the type of the variables. To Java, the String 2. String twenty two, theyre both characters arranged in a specific way. Now I dont want to go into too much detail about types, as this is better suited to programming basic concept 3 Data Structures. So thats all I will touch on for now, but no worries, it will all make sense in time Want Free Access to my Best Java Courses Alright, so if youre read this far down the article, then youre clearly interested in learning how to code. You can currently get access to my 2 best courses on Java for free for 3. When you sign up youll receive login information to start learning about Java. A Java Parallel Calamity. Java SE 8. supports parallel bulk operations filtermapreduce. This is. C in this. Unfortunately, the parallel engine that supports this feature. Edward Harned eh at coopsoft dot. Senior Developer, Cooperative Software Systems, Inc. January, 2. 01. 1 2. August, 2. 01. 6This article is. Java. Part one deals with the problems of an. ForkJoin framework in a commercial development. This article deals with the devastating effects the. ForkJoin framework will have on parallel. Bulk Data Operations for Collections JEP 1. Java SE. 8. These articles are getting too lengthy for comfortable reading. Here is a. consolidation in PDF format that uses the articles points as. Much easier to digest. A little parallel background Parallel. Massively. Parallel Processing MPP on clusters of computers and. Symmetric. Multiprocessing SMP often called shared memory. ForkJoin. splitting the work into fragments and joining the results together. SMP computers. ForkJoin. Separating the. problem into components, placing each component into a queue for. Component processing frequently called Task. Parallelism is a common procedure in the commercial application. Dividing a. problem into two or more sub problems, solving the sub problems in. Dynamic. decomposition frequently called Data Parallelism is a common. Recursive decomposition is a derivative of dynamic. The ForkJoin Framework in Java SE 7 uses. The framework. divides a problem into two sub problems left, right, forks left. Each. sub problem divides the sub problem into two sub problems left. Until it. reaches a threshold where it solves each sub problem in parallel. Dynamic. decomposition has a very narrow performance window It needs a. If you need to. sum an array of one million integers, then it is beneficial to. ForkJoin. It needs a low. If you have N processors and. N concurrent requests, then using one thread per request. The logic here is simple. If you have N processors available and you split your work. Try it yourself. You can. FJ vs. Thread Pool demo below. Recursive. In addition. Directed Acyclic. Graphswhere there are. Parallel Operations in Java SE 8. The JDK1. 8. engineers are using the recursively decomposing FJ framework, with. They also maintain that since the FJ framework is already inside. JDK, they use what they have. Using the FJ framework for niche processing in JDK1. A Java Fork Join Calamity. Using this framework as the parallel engine for all Java parallel. The Java SE 7 FJ framework is the academic experiment cited in. Its design is to. It is a great tool for teaching students how to walk down. It is not a general purpose. The four biggest problems with this. Part one has an. extensive write up on complexity. JDK1. 8. And for the. Java EE cannot use any of the. None. Nada. Zilch. Zippo. Submission Queues. The framework. puts the initial task into a submission queue. Since the framework. Submission. queues only exist because the work stealing deques do not permit. Only the owner work thread puts tasks. That is a good property only. See A Java ForkJoin Framework, section 4. Task. Locality, the framework is optimized for the. As seen in the figure, in most programs, the. But it makes. other work threads continuously scan for work and it means the load. The performance. benefit of this work stealing scheme is primarily for the. That is, processing a balanced tree structure DAG using. Commercial application development is. Why is this a problem The complexity. It may seem trivial reading this description here, but the. The. proof is in the code. The current version for JDK1. JDK1. 8 source code. Worker threads. must wake up and go looking for work. When to wake. up,where to look. Just to gain a little speed when processing a balanced tree. A simple FIFO queue is. The framework. has severe performance problems on first usage since it must. From the architect. Really. terrible. The performance. An appalling attempt at resolving this enigma is the. Submitting work to threads directly is a fast. After all, direct submission of new. CPUs is what operating systems do. Compounding the. submission queue quandary, is the practice of putting forked tasks. The start upscanfetch performance degradation of a. The real problem comes when running this framework. When using the. common Fork. Join. Pool, even though the work threads must finish one. When using. separate Fork. Join. Pool instances, the scanfetch CPU overhead. CPUs. Simply known in the developer world as not playing nice with. Submitters as workers. An additional. dilemma with submission queues is that the framework sometimes. Fork Join Worker Threads. That is, the. submitting thread executes tasks inside the framework as a worker. Instead of the framework putting the task into a submission. ForkJoin structure. While that. helps to get the process moving quicker than waiting for a worker. Why is this a. problemThe submitting. Uncaught. Exception. Handler is in effect which will adversely. ErrorException occur in the. When an. ErrorException occurs in stream processing, the stream should. However, since the. You can download the source code for a demo that. Exception in stream processing, Quiesce. Error. java. below. The submitting. Permissions leak into the framework code base not from a. Fork. Join. Worker. Thread. Factory which may lead to unforeseeable. The submitting. threads stack is contaminated with work that should be independent. If the. submitting thread started a transaction and a task executing in the. The same. scenario can apply for database management systems or other. JNI. An. unpredictable situation faces languages that use the JVM Clojure. Groovy, Scala, etc. This practice. Common Pool Submitter. The common. submitter queue for the common Fork. Join. Pool is also highly. The queue is a LIFO queue so precedence is given to. Consider the following. Recursive. Action tasks protected. Work else My. Job left  . My. Job data, lo 1 My. Job right. new My. Job data, hi 1 invoke. Allleft. right   This is known as. For lengthy splitting it can mean huge heap usage. Out. Of. Memory. Errors since all the Futurelt T objects. List after List after List. LIFO processing. proves disastrous for the new Completable. Future. When an async task. Stack. Overflow. Exception. You can download the. CFFailure. java, below. Also in that download is the the another. Completable. Future when using a large number of. Multi. Completables. Submission. queues are a poor choice for general purpose, commercial. Intermediate JoinRecursive decomposition using dyadic recursive. The only place to hold the intermediate result of the. Answer right. compute left. Answer   left. join returnleft. Answer. right. Answer Using the simple. Consequently. the use of an intermediate join requires a context switch to free. Without a context switch, the program will. The framework does not do, and cannot do, a. Part one has an extensive. Why is this a. problem Just like the. Employing this. framework for a stream of operations and many concurrent users may. A hypothetical multiple operation such as. Of. Weights blocks. Stream. filterb b. Color RED. mapb b. Weight. sum can result in. FJ framework. Now add dozens of concurrent.