TechTip: Getting Your Feet Wet with Java

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Java debuted in 1996—and while almost 20 years old, it's simply amazing how it continues to redefine itself and stay relevant. Still haven't tried it? No worries. Take a peek inside to see what Java can offer you!

 

Java has been around for quite some time now, and several recent polls suggest that Java is the top programming language that job seekers should know. That said, whether "the top" is Java, C++, Python, etc., the point is that Java is as relevant now as ever, so it's definitely something worthy of a presence on your resume.

Some Background

Java is a strongly typed objected-oriented (OO) programming language, originally designed by James Gosling of Sun Microsystems, that runs within a logical container called a Java Virtual Machine (JVM). The JVM provides a platform-independent mechanism by which Java code can be executed—the whole "write once, run anywhere"  (WORA) philosophy. This is a huge benefit in that your code that you developed on Windows will also work on Linux, OS X, IBM i, and so on. As a programmer, this is an extremely liberating feeling—knowing that the code you developed will behave consistently (in most cases) across various platforms; it also provides a significant savings from a quality-assurance perspective as test matrices can be significantly reduced with minimal risk in terms of platform-specific issues.

 

While Java's first release was in January of 1996, it wasn't until its 1.2 release in 1998 that the language really started to make a name for itself and become a serious contender with languages such as C and C++. From 1996 through 2006, new versions of Java were being published approximately every two years—each version adding new core libraries to solve the era's problems. Java's current version, known as Java SE 8, was released in March of 2014 by Oracle Corporation, who acquired Sun Microsystems in January of 2010.

Various Flavors of Java

Java is quite versatile; it comes in various shapes and sizes, depending on your business needs:

  1. Standard Edition (Java SE)—primarily used for desktop applications
  2. Enterprise Edition (Java EE)—primarily used for enterprise web applications
  3. Micro Edition (Java ME)—primarily used for resource constrained environments (e.g., mobile phones)

 

So depending on your requirements, there is most definitely an edition of Java to satisfy your needs.

Community

One of the best things about Java is the people. I can't stress this enough! There's a vast community built around Java, and it's almost impossible to find yourself in a situation that others haven't already been in; you're only a few web searches or blog posts away from finding an answer to your question. Architectural patterns, implementation patterns, development environments, performance tools, test frameworks—all are always just a few clicks away. This means less time spent reinventing the wheel and more time focusing on your business problems.

Getting Started

All right, enough talk. Now it's time to actually create your first Java application:

  1. Download the Java Standard Edition Development Kit (aka Java SDK). This provides you with the ability to create Java applications as it ships with tools such as the compiler and documentation generators.
  2. Ensure the Java SDK's "bin" directory is in your environment's PATH (so you can run its commands from a terminal window).
  3. Open a terminal session within your operating system.
  4. From any base directory in your file system, create a new directory called "test" and change directories into it.
  5. Using your favorite editor (e.g., Notepad, Vim, Emacs, etc.), create a new file called HelloWorld.java with the following contents:

    package test;

    public class HelloWorld {
         public static void main(String[] args) {
             System.out.println("Hello world!");
             System.exit(0);
         }
    }

  6. Type [javac HelloWorld.java] to compile your program.
  7. Type [cd ..] to go up one directory level.
  8. Type [java test.HelloWorld] to run your application; you should see "Hello world!" get printed to the screen.
  9. That's all there is to it! You just created your first application!

 

While any editor will suffice, I strongly recommend downloading Eclipse for a more integrated experience. Eclipse will automatically compile your Java code (i.e., the .java files) into byte code (i.e., the respective .class files) that can be understood by a JVM and save you a lot of hassling with such boilerplate tasks. The book Eclipse: Step by Step can help you find your way around.

 

While this is certainly a trivial application, you should now have a basic understanding of how to create, compile, and run a Java application. Extending your examples into the world of Java EE development would be a good next step—and as I previously mentioned, there is a wealth of online material in terms of blogs, wikis, tutorials, videos, etc., which can help you further develop your "hands-on" knowledge of Java. And if you're really feeling adventurous, try using Java ME to develop a new application for your mobile device!

 

Happy coding!

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