In the below, I will be presenting java source code of popular sorting algorithms. The problem with so many books I have read is that they don’t provide the simplest of solutions. I always consider myself an Hello World programmer. If I pick a new language, the first thing I look for is hello world, if I pick a concept, the first thing I look for is the simplest implementation, not the most optimized solution. NO. So when I look for implementations of algorithms, even if you are going to present me the most optimized algorithm, let me see the simplest, non-optimized implementation first.

When someone asked me why am I using for example, java.util.logging instead of log4j, I tell them, so far java.util.logging is working and I am yet to see a case I can not easily handle with it. So it is with these algorithms, let the reader/student see the simple solution and then present him with the problems with the simple solution, and then the optimized, more difficult to implement solution. If he likes, he can go with the simple implementation, when he finally discovered the problems with the simple implementation himself, it will be easier to understand the complex ones.

The programs below are very simple. Non of them have been optimized, they are meant to introduce to you these algorithms. You can take the code and optimize all you want. I also take care to use only simple data structures, no Lists, or Sets or any class in the collections package.

The below code are just segments of the full code. The important segments. The full source code is publicly hosted on Github

Finally if you want to read-up on these algorithms, please head to wikipedia
BUBBLE SORT

The algorithm below is based on the assumption that after every run through the array, the last element is already sorted.

So
for run1, the nth element is sorted,
for run2, the n-1th element is sorted,
for run3, the n-2th element is sorted, etc

	public void sortList(int n) {
		boolean swapped = true;
		while(swapped) {
			swapped = false;
			for(int i = 1; i < n; i++) {
				if (toSort[i] < toSort[i - 1]) {
					swap(i, i - 1);
					swapped = true;
				}
			}
			printArray();
			n = n -1;
		}
	}

INSERTION

	public void algorithm() {
		for(int i = 1; i < toSort.length; i++) {
			int key = toSort[i];
			int k = i - 1;
			while(k >= 0 && toSort[k] > key) {
				toSort[k + 1] = toSort[k];
				k--;
			}
			toSort[k + 1] = key;
		}
	}

SELECTION

	private void sortList(int startIndex) {
		int minIndex = findMinimum(startIndex);
		if(minIndex != startIndex) {
			//swap
			int temp = toSort[minIndex];
			toSort[minIndex] = toSort[startIndex];
			toSort[startIndex] = temp;
		}
		startIndex++;
		if(startIndex < toSort.length) {
			//recursively call sortList
			sortList(startIndex);
		}
	}

	public int findMinimum(int startIndex) {
		int min = toSort[startIndex];
		int minIndex = startIndex;

		for(int i = (startIndex + 1); i < toSort.length; i++) {
			if(min > toSort[i]) {
				min = toSort[i];
				minIndex = i;
			}
		}
		return minIndex;
	}

In the Part 2 of this post, I will show codes for MergeSort, QuickSort and HeapSort.

Source Code: Github
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If you are still wondering what CN1 is, please head to CN1 Website and read up about it for yourself.

I am going to be doing a series of tutorials or useful code snippets for CN1. Today we are looking at the ads component.

To use codename one ads, you need to register and have an account on inner active

Here are the steps to getting your ads on your CN1 app

1. Create an account on inner active
2. After login in, click the Add App tab and provide details for your app. The trick is to create different apps for different platforms so that inner active don’t go displaying a download app link on the appstore to blackberry users. You can also profile by age group and/or location.
3. For every App you added like this, inner active will generate a unique key for you. Key this key.
4. Now in your code, create an hash table that holds all the keys mapped to the specific platform and populate it. Then write a method as in below to add the ads component to the form.

    public static final Hashtable adKeys = new Hashtable();
    .............
    adKeys.put("rim", "[inner_active_rim_ad_key]);
    adKeys.put("and", "[inner_active_android_ad_key]");
    adKeys.put("me", "[inner_active_others_ad_key]]");
    ......................
    public static void showAds(Form f) {
        Ads ads = new Ads(adKeys.get(Display.getInstance().getPlatformName()).toString());
        if (!f.contains(ads)) {
            f.addComponent(BorderLayout.NORTH, ads);
        }
    }

Now for every page where I want to show the ad, I just call the above method and pass the form instance. Notice however that all my forms are BorderLayout and the North part is reserved for ads.

If you want to however use any type of layout other than border layout, you can use this code to add the ads component to the top of the page

Ads ads = new Ads(Helpers.adKeys.get(Display.getInstance().getPlatformName()).toString());
if (!f.contains(ads)) {
f.addComponent(0, ads);
}

That’s it, you now have Ads. You can visit your inneractive dashboard to see how your App is doing.

Back in 2001 when I started reading about this new programming language  called Java, I have only being a programmer for a few months and I see nothing serious about the mantra, “write once, run anywhere“. Don’t blame me, I have just learnt how to make a div jump using javascript and wrote a few arithmetic functions in pascal.

Fast forward to 2003, I have read about C/C++ and I have done more than my fare share of pascal, I never really got the hang of web programming, so I really suck at javascript then, but once again I started reading about Java and this time around something really caught my attention: The book I was reading said “Java can run on anything that has a memory and a microprocessor“. The author said,

soon your fridge will be able to determine when you are low on say milk and automatically make an order using you predefined credit card, soon, you TV will be able to send emails, soon, your credit card will be able to store more information that your account number, and these will be made possible by java.

Now those are pretty big claims to make in 2003, now? not anymore, even though your fridge can’t yet make orders, but the possibility is there and is not really something very difficult to do. But I digress, last week I was installing JRE for a client and Oracle said on the installer that Java runs on 2.5 billion devices! Great numbers right? but no, those numbers meant nothing to me if Java can’t run on iOS. iOS is the biggest mobile operating system out there and powers millions (if not billions) of devices and yet, Java can’t run on them. Those iOS devices are actually in every home right now (maybe not), but the point is Java could run on a gazillion devices, but they meant nothing if it isn’t running where it matters. One can argue that Java powers Android devices, yes, but that doesn’t dispute the fact that iOS devices are actually very important if you are an app developer.

Another place where Java is failing in it’s promises is the write once, run everywhere mantra, no it doesn’t work for mobile devices. There’s no way your can write once and run everywhere in mobile space, you write and write and write and hope and pray it runs on a few devices.

But all that is about to change. Enter Codename One. I don’t even know how to define what Codename One is, all I know is

1. Now you can write once and run on every mobile platform.
2. Your Java code can finally be made to run on iOS devices.

You can head to the Codename One Website to learn more about the goodies that it has to offer. I have successfully tested and seen a single code base running on Android (ICS), Blackberry (OS 4.2 and above) and Java ME feature phones (MIDP 2.0 and CLDC 1.0 and above). I didn’t have to make any changes to the codebase, and believe me the UI looks pretty cool.

Development is also easy, all you need is Netbeans. It comes with a GUI builder and a Simulator. One thing you will notice again is that the Simulator is fast. Very fast! Have you tried to develop for Android and Blackberry? Then you will notice that the Codename One Simulator is order of magnitude fast.

If you’ve been following the mobile app development space for a while, you would have heard of LWUIT, Codename One is built on LWUIT but is far more than that, the GUI Builder generates one of the most efficient code I have seen a GUI Builder generate. It throws away most of the fluff GUI Builders add to your code. It also builds your GUI as a state machine, such that you can think of your application as a series of states.

I can go on and on.

Codename One is currently in private beta and I believe beta is not far out (I am not speaking on behalf of the developers, but based on my perceived success of the private beta). I recommend you give it a try, you’ll be amazed.

Below are some sample screen shots from the application I built using Codename One private beta

twitpic.com/8nc5if yfrog.com/kio3ivp yfrog.com/oessyqp yfrog.com/kjm7rgp

And here is a live application

J2ME and RIM: http://www.getjar.com/mwc12

Android: https://market.android.com/details?id=com.israelmobilesummit.mwcevents&feature=search_result#?t=W251bGwsMSwxLDEsImNvbS5pc3JhZWxtb2JpbGVzdW1taXQubXdjZXZlbnRzIl0.

iOS: http://itunes.apple.com/us/app/mobile-world-congress-events/id497801040?ls=1&mt=8

Java, the Complete Reference, 8th Edition has been updated according to changes in Java 7. For those not willing to read the whole review, I will say my conclusion is, be you a beginner or an expert Java developer, you need to read this book.

This book is an in-depth guide to the Java language. A very large portion of the core Java APIs are discussed comprehensively. The book has four parts, plus appendix and index.

PART 1: The Java Language

This part has 14 chapters and comprises discussions ranging from the simplest to the fairly complex. It starts with a history of Java and ends with a discussion on Generics, touching topics like Annotations, IO, Threading and Exceptions along the way. I particularly like the part that talks about C programming language, extolling the virtues of the language. Of course no Java book is complete without talking about OOP (Object oriented Programming) and chapter 2 of part 1 did justice to this. One good thing for beginners is that you start writing code straight from chapter 2. If you are an experienced programmer, you can safely skip to chapter 10. Although I recommend reading everything.

Chapter 1: The Introduction and Evolution of Java

Chapter: 2: An Overview of Java

Chapter: 3: Data Types, Variables and Arrays

Chapter: 4: Operators

Chapter: 5: Control Statements

Chapter: 6: Introducing Classes

Chapter: 7: A closer look at methods and classes

Chapter: 8: Inheritance

Chapter: 9: Packages and Interfaces

Chapter: 10: Exception Handling

Chapter: 11: Multithreaded Programming

Chapter 12: Enumerations, Autoboxing, and Annotations (metadata)

Chapter 13: I/O, Applets and Other topics

Chapter 14: Generics

PART 2: The Java Library

This part also has 14 chapters, taking the chapters count to 28. Here the book discusses the core Java Library; which includes Strings, NIO, Networking, java.util package, AWT, concurrency and Regular Expressions. This is the chapter for you if you are an experienced developer. Here, the book discusses the new Java 7 Features and more. I’ll advice beginners to read the Part 1 at least twice before diving into Part 2.

Chapter 15: String Handling

Chapter: 16: Exploring java.lang

Chapter: 17: java.util Part 1: The collections framework

Chapter: 18: java.util Part 2: More Utility Classes

Chapter: 19: Input/Output: Exploring java.io

Chapter: 20: Exploring NIO

Chapter: 21: Networking

Chapter: 22: The Applet Class

Chapter: 23: Event Handling

Chapter: 24: Introducing the AWT: Working with Windows, Graphics and Text

Chapter: 25: Using AWT Controls: Layout Managers and Menus

Chapter 26: Images

Chapter 27: The Concurrent Utilities

Chapter 28: Regular Expressions and Other Packages

PART 3:  Software Development Using Java

This part discusses some really very import ant Java concepts. It contains just 4 fully packed chapters, recommended for both beginners and experts alike

Chapter 29: Java Beans

Chapter 30: Introducing Swing

Chapter 31: Exploring Swing

Chapter 32: Servlets

PART 4: Applying Java

In this part, we have two chapters. Each chapter picks a real world Java application. describes and implemented it. A note to beginners here, because of the volume of code you will be required to type, you might want to do copy-and-paste, but I strongly recommended against that. Doing the typing will definitely help you in more ways than one. This chapter concludes this book, bringing the number of chapters to 34.

Chapter 33: Financial Applets and Servlets

Chapter 34: Creating a download manager in Java

Appendix and Index.

In the appendix, javadoc is discussed. I particularly like and recommend this part to all. Documenting code is very important and should be embraced by all.

In summary, this is a good book, read it, study it, use it as a reference, whatever you decided to do with this book, you will find out it is more than equal to the task.

Great thanks to Faltermeier Bettina for providing me the preview copy.

The reason why I hissed was I was pissed, why Linux and Solaris, and now I couldn’t use VM? I went back to the Guide to see why, but the reasons given wasn’t convincing, so I went ahead and started the deployment on my mac. My disobedience paid off, not only did it work on a Mac, I was able to setup other Nodes using VM running on the same Box.

I have two VMs running headless. The type of Networking is Bridged. I have a wireless router that also has ethernet port, I hooked my Mac up on both the wireless and the LAN. I use the LAN for the Brigded networking on the VMs and the WIFI for my MAC.

This is all the setup you will need. Note that of you have read the Admin guide, you will see things like node1, node2 etc used to name the systems on which the different instances of the NoSQL DB is running, to avoid having to go into naming and hosts file and that, we will just use the IP addresses, they also work.

I am going to assume that my MAC ip address is 192.168.1.4, and the VMs are 192.168.1.5 and 192.168.1.6 respectively.

After installing the NoSQL DB on all three machines (My MAC and the two VMs.), I run the below commands in the same directory as where the NoSQL DB is installed.

mkdir Data
./bin/kvctl makebootconfig -root Data -port 5000 -admin 5001 -host 192.168.1.[4,5 or 6] -harange 5010,5020
./bin/kvctl start -host 192.168.1.[4,5 or 6] -root Data

The above will create a config in /Data and start the NoSQL DB.

Next, you need to run the below command on 192.168.1.4 only

./bin/kvctl runadmin -port 5000 -host 192.168.1.4 -script script.plan.txt

The content of script.plan.txt is

configure mystore
plan -execute -name "Deploy Boston DC" deploy-datacenter "Boston" "Savvis"
plan -execute -name "Deploy Node1" deploy-sn 1 192.168.1.4 5000
plan -execute -name "Deploy Admin" deploy-admin 1 5001
addpool BostonPool
joinpool BostonPool 1
plan -execute -name "Deploy Node2" deploy-sn 1 192.168.1.5 5000
joinpool BostonPool 2
plan -execute -name "Deploy Node3" deploy-sn 1 192.168.1.6 5000
joinpool BostonPool 3
plan -execute -name "Deploy the Store" deploy-store BostonPool 3 300
quit

If all went well, visit 192.168.1.4:5001 from you browser and click on topology.

For a description of the commands in the script.plan.txt see the Adming Guide.

My first attempt at using an IDE was KAWA, It was heaven. After a bit of tinkering here and there, I can finally get code completion to work. And the code completion has javadocs embedded. It was fun. I loved KAWA, but I knew I needed more. I tried several other IDEs and Editors, but KAWA was the clear winner then. At least until I met JBuilder.

JBuilder was the hallmark of my programming career. At last I can get syntax coloration, code completion, javadocs, on the fly error checking (unlike KAWA, I still have to compile to see errors), etc etc. I can even set it up for JavaME, which then didn’t have any integration with any IDE. At last I wasn’t the brunt of those jokes anymore. I now have a worthy IDE. We found another sucker, a classmate that uses McAfee Antivirus. We usually taunt him that McAfee can catch itself as a virus if given the proper settings.

A few months later, I was introduced to Netbeans. And a few weeks down the line, eclipse. To be sincere, at this time none of these IDEs can compete with JBuilder, But I have a choice to make, Netbeans, Eclipse or JBuilder. Once again I chose Netbeans. And sincerely, Eclipse was better at this time. Eclipse had more community behind it than Netbeans, and JBuilder was the best of all. What informed my decision was two questions.

• Who is the custodian of Java?
• Who made Netbeans?

I saw that one day, there would be new features in Java that only Netbeans will support, at least for a while. I saw that someday, The other IDEs would have to play catchup since Netbeans will always be one step ahead. And that day has come. Netbeans was the first to support Java 7, the first to support Java EE 6, the first to support JavaFX 2.0, and now with Netbeans 7.1 beta, Netbeans is finally one step ahead of all other IDEs. With several features that most IDEs still dream to have, my choice finally made sense.

After JavaOne 2011, I see the other IDEs still playing catchup. JavaFX Roadmap is cool, which will be the first IDE to support the new features? JavaME roadmap is cool, which will be the first IDE to support all the new features? Java 8 is also in the works. There wasn’t even a mention of Oracle JDeveloper in JavaOne, it is a clear message as to the commitment of Oracle to Netbeans. In my mind, I see the IDE wars as being won, at least for another 3 to 4 years.
Follow @trinisoftinc

Recently I made a website, http://www.unotifier.com. It is a single hub for sending notification alerts via email and/or SMS. The website is built using JSF and Java EE (Web). These series of posts will take a look at the code powering it and try to use it to explain JSF and Java EE. Be warned that this is not an in-depth discussion about JSF/Java EE, I will just highlight some parts of JSF/Java EE that I used in designing the site.

 The architecture is simple, the views are JSF pages, Managed Beans and Servlets, the persistence layer is pure JPA (I have since given up on Hibernate for personal reasons). I use session beans for all persistence logic, e.g create, delete, update, search etc. Most of the code in the session beans are generated by Netbeans. No worries if you don’t understand these buzz words, It is just JEE way of saying MVC.

 So back to unotifier, in this post I will be taking a look at the front end, in subsequent posts I will talk about the back-end. As I said earlier the front-end is basically JSF and some servlets, I also use components from the Primefaces component framework.

 THE TEMPLATE

JSF allows you to define a template file that can then be used through out your website. The template file define names for particular parts of the page and the page using the template file can then define contents for these parts. Take a look at a sample template file

layout.xhtml

<html xmlns="http://www.w3.org/1999/xhtml" xmlns:h="http://java.sun.com/jsf/html" xmlns:ui="http://java.sun.com/jsf/facelets">

<head>
	<ui:insert name='title'>
		Default Title
	</ui:insert>
</head>
<body>
	<div id='head'>
		Default top contents
	</div>
	<div id='center'>
		Default center contents
	</div>
	<div id='foot'>
		Default foot contents
	</div>
	<div id='right'>
		Default right contents
	</div>
</body>
</html>

This is basically what the unotifier template file looks like. If you take a look at the website again you can see each of the ui:insert defined right?

The head is the logo part of the site

The footer is where you have the contact informations

The center is the main contents area

The right is the place where you have the register and login forms.

Now since the header is never going to change for this website, I included the contents in the template file, and same as the footer. So in my web pages I only override the right hand side and the center.

A page that uses the above template file can look like this.

Home.xhtml

<html xmlns="http://www.w3.org/1999/xhtml" xmlns:h="http://java.sun.com/jsf/html" xmlns:ui="http://java.sun.com/jsf/facelets">
	<ui:composition template='layout.xhtml'>
		<ui:define name='title'>Unotifier - Home Page</ui:define>
		<ui:define name='center'>
			Hello all, this is the center area
		</ui:define>
		…............
	</ui:composition
</html>

Any part of the template file that you define using ui:define will have a content different from what you specified in the template, else the default contents in the template file are used.

Take a look at http://www.unotifier.com/sent/views/index.xhtml for a sample file that shows the default template for unotifier. The page did not override any of the contents in the template file.

The ability to define templates like this is very important. You can define a part of your page that doesn’t change much in the template file and you are sure not going to have to do the dirty copy and paste every time you need this content. It also keeps your code clean and easy to maintain.

THE PAGES.

If you had taken time to register on the website, you will notice that you are always on a single page, home.xhtml even though not all the pages uses ajax. This is not to say that the code for unotifier is in a single page, no. I use another useful technique in JSF, includes and renders.

On the home page, the register form is a different JSF page, the login form is another page and the main contents is another JSF page. After login in, each of the parts of the page are different JSF pages, for example I have a settings.xhtml, add_client.xhtml, dialogs.xhtml, etc etc. JSF allows you to include these other JSF pages all in one page. JSF also have a render attribute for it’s components that takes a boolean value. This attribute tells the components either to show or not when the page loads, it’s like the css attribute display:none or display:block.

So to include another page in your page you say

<ui:include src='another_page.xhtml' />

and to do selective rendering

<h:form render="false">
</h:form>

That is all. This also helps a lot in keeping your code base organized.

THE COMPONENTS.

I can’t really say much about the components, all I can say is head to http://primefaces.org/showcase and see the wonders of primefaces for yourself.

What I can say though is this. The page uses a primefaces component called layout. If you are a Java Swing developer, this component is similar to your border layout. It has the North, South, Left, Right and Center sub-components that you can use to neatly and painlessly layout your website.

BACKING BEANS

Every other thing on the UI are basic JSF components, and primefaces components. JSF Components require backing beans to come alive, else they are just dummies, they won’t respond to you. A backing bean is also very simple. It is a POJO that contains methods, private variables and getters and setters. So for example the login form on unotifier have a backing bean that looks like this

/**
* @author trinisoftinc
*/
@ManagedBean(name = "loginController")
@SessionScoped
public class LoginController {

@EJB
private AdminFacade adminFacade;

private String l_email, l_password;
private static Logger logger = null;

/** Creates a new instance of LoginController */
public LoginController() {

}

public void doLogin() throws IOException {
   FacesContext context = FacesContext.getCurrentInstance();
   Admin admin = adminFacade.findByEmailAndPassword(l_email, l_password);
   if (admin == null) {
      context.addMessage(null, Main.doErrorMessage("Login Parameters incorrect"));
   } else if (!admin.isConfirmed()) {
      context.addMessage(null, Main.doErrorMessage("Please click the confirmation link in your email first."));
   } else {
      Map session = context.getExternalContext().getSessionMap();
      Main main = (Main) session.get("main");
      main.setLoggedInUser(admin);
   }
   l_email = "";
   l_password = "";
}

public String getL_email() {
   return l_email;
}

public void setL_email(String l_email) {
   this.l_email = l_email;
}

public String getL_password() {
   return l_password;
}

public void setL_password(String l_password) {
   this.l_password = l_password;
}

 and the JSF page itself looks like this

<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:h="http://java.sun.com/jsf/html"
      xmlns:ui="http://java.sun.com/jsf/facelets"
      xmlns:p="http://primefaces.prime.com.tr/ui">
    <h:form prependId="false" styleClass="login_form">
        <h:panelGrid columns="1">
            <p:inputText id="login_email" value="#{loginController.l_email}" requiredMessage="email can not be empty" required="true" />
            <p:watermark value="email" for="login_email"/>
            <p:password id="login_password" feedback="*" minLength="6" value="#{loginController.l_password}" required="true" requiredMessage="password can not be null" />
            <p:watermark for="login_password" value="password" />
            <p:commandButton value="Login" actionListener="#{loginController.doLogin()}" ajax="false"/>
            <h:commandLink value="forgot password?" onclick="forgot_password.show(); return false;" />
        </h:panelGrid>
    </h:form>
</html>

So the inputTexts (TextFields) have values that are tied to variables in the backing beans and the commandButton have actionListener that is a method in the backing beans. When the button is clicked, the variables take the values from the textfields and the method doLogin() is called. ajax=false says page should refresh and ajax should not be used. If you forget to specify getters and setters for the private variables, the JSF page won’t see them.

This is how most simple JSF pages look like. Of course there are some complex ones that use phase listeners, validators, converters etc. All these are simple concepts that can be easily grasped if/when you need them.

And that is the UI for unotifier.

I needed a captcha for a Java Web Project, I tried SimpleCaptha and ReCaptha….both worked fine. And then out of curiosity I checked wikipedia what a captcha is and this is what I got.

 It is an acronym based on the word “capture” and standing for “Completely Automated PublicTuring test to tell Computers and Humans Apart”

So basically, we want to be able to tell computers (or bots) trying to use our service from humans. So I thought to myself, is it really necessary to use all these mangled, difficult to read, sometimes very funny images? We can just ask the user a simple question we think only a human can know, make this question random enough that guessing(which is what most brute force attacks rely on) will be difficult.

For example, I am yet to see someone who says he/she has successfully guessed a recharge voucher pin. Even if there are maybe one or two. And this pin is just numbers, sometimes as few as 10 digits. Your ATM Pin is most times 4 Digits.

I remember seeing on a website a very simple captcha, they ask you a mathematical question, (+, -, *) and you give an answer. That simple. No mangled image, no mangled audio, nothing fancy.

So I started writing down ideas for what we can really call SimpleCaptcha.

1. Present five random characters and ask the user what is the n-th character, of course the n-th character is also random
2. Present the user a simple arithmetic expression, and ask for the answer. The two operands and the operator are random.
3. Ask Date based questions like today is thursday, two days before today is ?, yesterday was Friday, 9 days from now is, etc

Now these captcha ideas MAY or MAY NOT have very very serious security holes. I am not an expert in web security and captcha, I am just a guy who likes simple things.

Below is some part of the Single File Java Class that does No. 2.

    public String getQuestion() {
        Random r = new Random(System.currentTimeMillis());

        int operationRandInt = r.nextInt(3);
        String operationString = operations[operationRandInt];

        int q1Rand = r.nextInt(100) + 10;
        int q2Rand = r.nextInt(100) + 10;

        //we don't want answers to have -negative results
        if (operationString.equals("-")) {
            while (q2Rand >= q1Rand) {
                q2Rand = r.nextInt(100) + 10;
            }
        }

        /*
            if you want to implement for division, be my guest.
            A few thoughts though.
         * 1. It will be easier if there are no reminders in answers. i.e q1/q2 = Whole Number
         * 2. It will be safer if q1 != q2.
         */

        q1 = q1Rand;
        q2 = q2Rand;
        operation = operationString;

        return q1 + " " + operation + " " + q2;
    }
    public boolean solve(int answer) {
        if (operation.equals("+")) {
            return q1 + q2 == answer;
        } else if (operation.equals("-")) {
            return q1 - q2 == answer;
        } else if (operation.equals("*")) {
            return q1 * q2 == answer;
        }
        return false;
    }

The full source is here Captcha.java

We have a Spooler S, and a Processor P.

S spools jobs and P processes them.

S can spool 3 jobs per second, while P can process 1 job per second.

We can only have one S but as many Ps as possible.

Since S is three times faster than P, we can assume that for every S start, we need to start 3P. This assumption is WRONG.

If we start S and 3P at the same time, 3P will actually sit idle for a second before they start processing records.

So we need to start 3P after S has spooled the first job. While each of the P is processing the job, S can spool another 3. So every one is happy.

Since we can have as many Ps as we want, we decide to have 9Ps.

We can also assume that we should start 9P after S has completed 3 jobs. WRONG AGAIN

If we go by the above assumption, 9P will process 9 jobs while S fetches 3 jobs.

On the next second, there will be 9P but 3 jobs, so oly 3Ps will be working, 6Ps will be idle, this happens all the time after the first second.

We don’t like idle Ps. So we decided to allow S run 90 times before we start 9P, so that each the Ps have 10 jobs waiting for them before they start.

If you are following me, you know that there will be a point where the Ps will catch up with S.

Questions:

1. Determine for 20Million jobs if the Ps will ever catch up with S
2. If the answer above is YES, then determine amount of jobs each P needs to be waiting for them before they start so that they can never catch up with s.
3. If answer above is NO, then determine how many jobs was needed for the Ps to catch up with S
4. Write a program that takes the number of Ps and The total amount of jobs needed as input. Your program should output how many jobs S needs to spool before we start the Ps such that they will never catch up with S.

e.g If we have 18 jobs and 6P, then S needs to spool 9 jobs before we start the Ps.

| seconds | jobs | processed | total rema |
| 1 | 3 | 0 | 3 |
| 2 | 3 | 0 | 6 |
| 3 | 3 | 0 | 9 |
| 4 | 3 | 6 | 6 |
| 5 | 3 | 6 | 3 |
| 6 | 3 | 6 | 3 |

Get answer in the comments

This post was inspired by Make Love Not Flame Wars

Hi Scala and the other “wannabes”,

This is a quote I heard somewhere.

You can know people with convoluted self esteems by how much they try to put other people down

The truth is I hate people like that. I know you can do some things better than I can, but please tell me what you can do, not how you are better than me.

This contractor walked into my office and talked for 30 mins, for 25 out of those 30 mins, he was telling me about his competitor and how he was better than him. The remaining 5 mins he told me some bollocks about how happy he would be if he got the job. What I did? I called the competitor and gave them the job. Why? He already told me what the competitor can do.

Dear Scala, please stop telling me how Java is retarded, I know. Stop showing me how you can do X in 1 LOC in Scala, but it will take a gazillion LOC in Java, I know. The problem I have with you is that you seem to be unable to successfully present yourself to me IN YOUR OWN LIGHT, but you just must find a way to trash Java so as to make you look good.

This was the attitude your distant cousin Ruby too some years past, where is she now? I hate her, not the kind of passionate hatred I have for PHP, or the kind of “dining with a long spoon” hatred I have for Python, but the kind of hatred that made me see Ruby as incompetent in herself. In fact, I am sure I might NEVER write another LOC in Ruby.

And your other half cousin Python, always wanting to be everything. Last time he was telling me how he is also functional and object oriented at the same time. I heard him trashing C, my old faithful and he was saying he is here to replace bash and shell the first time I met him.

Look Scala, I like you, and that is why I am writing you this letter. Tell me what you can do, and leave me to Judge if you can do it better than X or Y. Look at perl, he is not trying to be anything but perl. Look at erlang, he is not competing with anyone but himself, he tells you what he can do, and leaves you to decide. I love erlang. I want to love you too, but please stop being annoying. You are better than that. Tell me about how “functional” you are. Tell me about how you up hold “Object Orientation” in your core. Tell me the beauty of building a language on the JVM, let us know why it is so elegant to combine OOP with functional programing. You see all those wonderful things people have achieved through you, like Lift and AKKA and SPEC, tell me more about them. That is the stuffs I want to hear. If I see another LOC comparison again, that is it between us.

The truth is most of the boiler plate codes you show me in your LOC comparisons are rubbish. I never ever have to write those codes myself, that is the work of my IDE, netbeans handles those well. I also hear about IntelliJ and eclipse and how wonderful they are, so quit talking out of your ass, tell me something you know, not something you heard.

That is it, I hope this letter reaches you on time.

I am not hoping to hear from you soon, but if you deem it fit to respond, then fine, you know where to get me.

Your Sincere Admirer and Learner.