PHP to Java career change

You will notice that they are very different animals. Java technologies encompass a wide array of software development where as PHP specializes in web development. With that being said probably the easiest thing for you to pick up will be JSP pages.

To be a good Java developer who is worth hiring I expect a thorough understanding of the following concepts.

1) The Java Runtime Environment, interpretation of byte code, garbage collection, command line interpretation, etc... 2) Java compiler, compilation of Java source code into platform independent byte code, invoking from the command line. 3) The Classpath 4) Basic syntax 5) Thorough understanding of the standard libraries

These are all vitally important to understand but are just as important as universal developer knowledge such as the SDLC, best practices, etc...

I commend you for trying something new, but with that being said you will have an uphill battle without direct Java experience on your resume. I am not making any unjust assertions about you, but their are a lot of PHP programmers who don't understand how to write software that scales to the enterprise level. I am sure that you have experienced a few in your career.

As someone who interviews Java developers and influences hiring decisions, I am very careful about evaluating candidates who have a large amount of PHP on their resumes by being very thorough in technical as well as general enterprise development knowledge.

The main problem with PHP programmers going to Java (or C#) is that with PHP you can get away without writing object oriented code, and the libraries were meant to be so modular that they may look as "random pieces of code". However, in a language like Java or C#, object orientation is everything and they have massive libraries working in sometimes a tight integration.

I'm not saying that you really shouldn't go for it, but just beware, coming from a weak typed language to a strong typed language which is also purely OO, the learning curve should be steep at best. So ,I urge you to make some real project on Java and then move into a Job (consider freelancing some Java job).

On the other hand, if you feel very confident and you see you can learn (reaally) fast, then give it go, like someone said: "You need to follow your heart" and it should be allright.

Hope I'm not too pesimistic, :)

I don't think your problem is going to be learning java, since you're probably more than capable of downloading eclipse and opening a book and reading, trying examples, etc. I think re-implementing a php project in java is a good starting point. But the problem is likely going to be finding a job in java. Er....or rather finding a job that someone will hire you for at a price you'll find acceptable.

It's like this. I was doing c for several years and I wanted to get into .NET. So I learned it on my own. I was actually pretty good at it at the end and so I started job shopping. Then I realized that there were two problems:

• The places that wanted to hire me were not willing to pay anything close to what I was already making. They were essentially low-balling junior engineer positions. So they didn't care what I knew.

• The places that were probably going to pay an acceptable rate started in with "On, C is a procedural language, and .NET, well it's object oriented. Are you sure this is something you can handle??" And nothing I could say in an interview was going to convince them that I was capable. In retrospect I'm not sure why they brought me in to interview, but...anyway!

So what happened? Am I still coding in c? No, but I did find a job in c++ (I was later told that even in this case they felt I was a risky hire). And then my next job after that was c++ officially, but I ended up getting moved to a java project. And now I mostly do java. I've forgotten all the .NET stuff I learned several years back.

I'm not sure what the take-away is, except that it's really hard to move from one language to another (and especially when the languages are as different as php and java). Not because you're unable to do the job, but because of the risk you represent and the biases of hiring managers.

I migrated from PHP to Java too. I too had some prior basic knowledge and experience with Java. I would recommend this book: http://www.amazon.com/Professional-Java-JDK-Clay-Richardson/dp/0471777102

Unlike many others, it is not written for dummies, and does not contain corny things like "What is an object" or "how to run your first program". This book is a guide for beginners who want to become professionals.

Once you get past the syntax, there are a few more key concepts you should understand.

1. Unit testing -- learn junit. This should be similar to phpunit (if you have been using that).

2. Concurrency, threading, and event handling. Php does not have threading. It does permit file and record locking, so these concepts should not be entirely foreign to you. When you get faced with a situation where you have concurrency, please take the time to understand ACID, and how to do this in Java.

3. There are many packages that provide various, useful capabilities. This concept is similar to php libraries. The equivalent in Java is packages. There are packages that handle I/O, Networking, Collections, User Interfaces, Reflection etc. At any rate, you should become familiar with the JavaDoc API documentation, the key packages, and what capabilities they provide. You do not have to understand every single class and method, but you should understand how to search and find what you need.

4. You should get very intimate with Collections and Generics, understand jar files, and that, in addition to .class files, you can embed other types of files as well, such as images, sounds, text, XML, and any other file your package needs at run-time.

Even after years of writing Java code, I still occasionally refer to Sun^H^H^HOracle's Java Tutorial to refresh my memory on how specific packages work, or use a package I haven't had to yet. As you are learning the language, I would suggest that you go through the basics trail first, then others as you need them. For instance, if you need to read and write XML files, go through the JAXP trail.

There are also some open source frameworks that you should investigate:

• Struts for web site development
• Hibernate for databases
• Spring for general application development, and for applications that require integrating capabilities from multiple sources. A central focus of Spring is to allow for reusable business and data access objects that are not tied to specific J2EE services. Such objects can be reused across J2EE environments (web or EJB), standalone applications, test environments, etc without any hassle.