Java, Where To Start?

I'm a web developer who has design and programming experience. So, VB, ASP, PHP, Coldfusion, Perl, even C and C++ I have in my belt. I also use Dreamweaver and/or do a lot of my HTML/XHTML/JavaScript coding by hand. So, the DOM, DHTML, etc, all good to me and even OOP thinking and design I have when I code. And I even have MySQL and other databases, again, not an issue here. So, my weak point is — Java — I see so many jobs out there with J2EE, Hibernate, Eclipse, Netbeans. Beside the obvious, which is to learn Java the core language, I don't know where else to go from there. There is so much! What should I read? in what order? What software do I require? UML? Swing? I mean, what is the curriculum required for someone to say they are a solid Java developer? Even assuming I have to go through Java itself, what are the good books out there?

Comments

Wrox Press

[dnoyeb]

I started Visual C++ 5 with a book called "Beginning Visual C++ 5" by Ivor Horton from Wrox Press. When I started in Java I bought a book titled "Beginning Java" by Ivor Horton.

I would start there. Java is really straight forward OO language. The only issue you will have coming from C++ is to let go of destructors and realize Java does not use them. Many from C++ take about 6 months to stop tryng to make a finalizer into a destructor.

Re:Wrox Press

[jfim]

Does Java uses finalizers? If so, how do they differ from C++ destructors?

Yes, it does. They differ from C++ destructors as they are not called explicitly(or implicitly when variables get out of scope, as in C++). Rather, finalizers are called when an object is garbage collected.

The usual advice is not to use finalizers, except to make sure that underlying native resources are released(ie. file handles, sockets, etc.). Even then, there should be a mechanism to release those resources without relying on the finalizer being called, such as a close() method or an equivalent. The finalizer is only guaranteed to be called when the object is GC'ed, which may happen much later than expected if there is not a lot of pressure on the memory system or if there is still a reference to the object.

There is no guarantees that finalizers will ever be called for an object, as the VM can be forcibly interrupted via Runtime.halt() and finalization of all objects on VM shutdown can be disabled.

Thinking in Java

[yanyan]

Thinking in Java is nice. And it's free. http://www.mindview.net/Books/TIJ/

Thinking in Java

[lurker-11]

Thinking in Java is a good book on the Java language. You can read it online at the author's web site: http://www.mindview.net/Books/TIJ/

Try javabat.com

[icknay]

For basic coding practice, try the free http://javabat.com/ -- it has little coding problems (logic, strings, arrays, recursion) that run right in the browser, so you get immediate feedback. It's great for building skill in the basics, but it's no substitute for building larger programs. Disclaimer: I built it

Re:In the same boat...

[SirLurksAlot]

I started with Eclipse (as I use it for LAMP development) and switched to Tomcat

Ummm, what? Eclipse is an IDE, Tomcat is a container for web servers. Tomcat and Apache can be used with Eclipse with a nice little plugin for testing.

sun certified developer.

[leuk_he]

Sun has developed a program to train for java.

read at the sun site

java is relative simple. Those certification programs give you a guideline what is involved in certain roles. But java is MUCH and lots of simple libraries. that is what people underestimate.

I understand you might not need certification, but the knowledge described there gives a good idea what you need/can put on your CV.

Don't use Java

[Anonymous Coward]

As a person in charge of desktop imaging and 3rd level support at a company of 100,000 desktop and notebooks, I'd first say, "don't use Java at all". My second thought is, "well, if you must use it at all, use it only on the server.".

Unfortunately Sun, in its infinite wisdom, has no idea at all how to patch. They have security vulnerabilities all the time and they make you install a completely new version of Java in a new folder each time. Their "updates" leave the older vulnerable versions behind (and still accessible by malicious code). Their updates break applications all the time. We are constantly having to deal with issues like the current one we have: there are known vulnerabilities in JVM 1.6.0_05b13, but there are some serious problems with deploying the "fixed" version as it causes bizarre error messages and slows Internet Explorer down. Both are acknowledged bugs, but won't be fixed soon. So you end up stuck between securing the systems and having the systems actually work right.

Sun Java is a continual nightmare.

I'll say one thing from Microsoft - when you could use MS Java it never (not once in the several years we supported it) broke apps and patches were actually PATCHES and not whole new broken versions.

Java - just say no until they actually learn how to update and patch correctly.

Re:In the same boat...

[SirLurksAlot]

Ok, you're missing my point, which is that Eclipse and Tomcat have absolutely nothing to do with each other. You don't need to "switch" from one to the other because they are used for entirely different purposes. Yes, they're both tools, but it doesn't make any sense to tell the parent that you switched because one is used to write code and the other is used to serve applications. It makes you sound like you don't know what you are talking about, and will only confuse new developers.

Re:Don't

[Anonymous Coward]

As someone who's worked in Java with some of those 100.000 guys in India, they may know Java, but most don't know java well. The vast majority of programmers either here or there can solve a problem, but not consider the security risks in their solution, nor necessarily come up with an elegant design for doing so.

Having said that, I've used hibernate (once, to get it set up and configured, it works well enough we didn't have to go back and change it), struts/struts2, and tiles. Most of these are XML configuration rather than coding. If you can do make files, and handle any markup language, these won't be a problem.

It sounds like your main concern is learning java itself. Since you know C/C++ the syntax and conceptualizations won't jump out and bite you. I'd recommend grabbing a project that interests you (or that needs to be done), and just doing it. Use Eclipse, its tools will make your life MUCH easier (unless you like coding c/c++ in a vi-like environment, in which case by all means use emacs/vi/editor of choice). I'll probably get slammed for saying this, but learning java isn't any harder than learning VB, (easier than C/C++ which is what I'm currently picking up), it uses a different namespace, and slightly different approach, that's all. If you're a competent programmer (and from your post, it sounds like you are) then it's just going to take some time/hard work to get used to the new language's quirks.

My own recommendations

[mccalli]

Not recommending a book, just specifics of Java:

• Threading
  Ensure your concurrency skills are up to snuff. Read about the newer (1.5+ so not that new admittedly) ways of handling concurrency in Java - a lot of older books will miss the java.util.concurrent frameworks.
• JDBC
  Persistance frameworks are all well and good, but understand the fundamentals of how things work at the database level inside Java.
• Spring
  Although this changed a little with the latest rev of EJB, many sites simply dumped it and went with Spring. Worth knowing.
• Application servers
  Pick one and know one, use that to extrapolate to the rest. My own advice is to look at Tomcat, but just knowing the basic concepts behind them is a start.

There's probably a lot I've missed, but right now I'd consider looking at those.

Cheers,
Ian

Fail

[patio11]

You need to encapsulate that in a class. And your main method signature is wrong -- needs to take a String array as an argument, or else the program will say "No such method found (main)" and die.

Honestly, its almost like no one on Slashdot programs in Java some days... ;)

Re:I beg to disagree

[mrops]

Doing java dev for more than 10 years, I think this is a valid question. Java is not about the core J2SE anymore, I was fortunate that java evolved along with my career, so i picked things up as they came to market. Further google is excellent if you know what you are looking for, however in this case, the author does not even know what he is looking for.

Now to answer the question.

First read Just Java by Peter van der Linden (if I spelled the name correct). Excellent book.

Get Eclipse IDE and learn jdbc, JSP/servlets, and struts preferable in that order. Except for struts Just Java should give you a primer on each, struts has a decent website with tutorials.

I would skip EJB/J2EE for now and jump to spring and later hibernate. You will find great tutorials on their websites.

Somewhere along the process also introduce yourself to JNDI, particularly JNDI when it talks to LDAP, this is a given when u are coding an enterprise app.

At this point you would know enough to do a decent job as a java developer, more importantly you would know what to do next.

This is what I can think of on labour day long weekend :)

Re:I beg to disagree

[morgan_greywolf]

You have to start somewhere. Just like if you wanted to learn PHP, the PEAR toolkit, and Drupal or some other 'framework' for Web applications in PHP, or whatever. Or, as an example I'm more immediately familiar with would be knowing Python, mod_python, Django, WSGI and a database like MySQL or Postgres.

You start by learning Python. Then you move on to MySQL. And then you might learn mod_python and finally WSGI and then Django. But you have to start with one concept and move on the next and the next and the next until you have enough knowledge to cover what you need to know.

So with Java, you might start with Java, move on to Netbeans, etc. Learn any frameworks, etc. You start with one thing and move on to the next. YOu need to learn increasing levels of complexity. SO obviously you need to have a grounding in Java before you learn Swing. And Java basics before J2EE. And so forth.

Re:I beg to disagree

[ardle]

Look out for Java books by Cathy Sierra, very insightful and easy reading. Get to know Collections API (part of Java) early: you'll learn important stuff along the way that you can take anywhere.
As regards frameworks, take a look a Spring - but not until you understand core Java (the principles, not the libraries). Spring has a Web Container but Tomcat is better if starting from first principles (or, at least, it used to be good. It's the "reference" Servlet container, for what it's worth). EJB container: do it with Spring (or some such). JBoss has (is? I don't know any more) an EJB container. EJBs are low-priority: they're really just a kind of "sandbox" environment where resources are closely managed. Thankfully, that environment has just become easy to program.
As regards IDEs, Eclipse is what I use ATM. Most vendors' IDEs (IBM, Oracle) are built around Eclipse. It's pretty easy to run simple programs there but the interface isn't very familiar (jargon-wise) to newcomers. I hear that NetBeans is very good these days.

Re:I beg to disagree

[Doctor Memory]

1. Get a copy of Head First Java .
2. Download the latest version of Java.
3. Download Netbeans or Eclipse (I prefer Netbeans, but I use Eclipse at the office, and I don't have a problem recommending either one). Make sure you get a version that includes either Glassfish (Netbeans) or Tomcat (Eclipse), so you can run some servlets.
4. Start going through the book. You'll learn the Java syntax and conventions in the first part, then learn about web development. Since you've got web development experience, you can probably skip a lot of the intro (web apps use the HTTP request/response cycle, are stateless unless you stick stuff in the session, etc.) and dig into some JSPs.
5. Once you can get data from the browser to the server, pick up JDBC and stick it in the database. If you've used ODBC with VB, then you'll have no trouble picking up JDBC.
6. Pick up a Spring book (I'll recommend Spring in Action) and learn about dependency injection. It's a pretty simple concept, but you'll be amazed what you can do with it.

That should give you enough to get started and maybe even get your first Java gig. Hibernate's good to learn, too, but on most of the projects I've been on, you don't use it in day-to-day development (that is, you don't have to reconfigure or redeploy anything, unless your data model changes). With Spring, just about everything you write will require that you modify a context file or two, so you need to know what's going on.

Re:Don't

[EEBaum]

Portable? Clean? Try mobile development some time. Maintaining a large handful of project files because of different screen sizes is a joy, not to mention interacting with different phone providers' frameworks, plus a buttload of special-case code strewn about to deal with the inconsistencies and quirks (including missing and misbehaving features) of each device's particular implementation of the VM. Languages like C have a preprocessor that allows such variables to be put in #ifdef blocks... no such luck with Java. All that, and the program will look like absolute crap on anything but a phone.

Portability is a nice word that Java people like to throw around, but in my experience, the program has to be set up separately for just about every target. You can do that just as well with C (Brew, as far as phones are concerned), and without a handful of different project files to include or not include target-specific files.

Not to mention that, on comparable phones, Java performace is abysmal compared to Brew. Not fast.

Java has its place, where its benefits can be well exploited. That place is, as far as I've seen, largely restricted to situations where the systems it'll be running on are not terribly diverse, e.g. Linux servers, where portability really isn't that much of a concern.