I am looking to get back into Java programming after a hiatus of about 5 years after college since I took a job that did not deal with Java whatsoever. I was wondering what types of things someone looking to get into an entry level Java position should know, any sites that are helpful and where to find some "sample" problems (ie homework) that I would be able to play around with. I have basically started back at the beginning reading "Java for Dummies" and "Head First Java" as well as enrolled in a few pre-recorded classes online. Any and all information is much appreciated, thanks in advance!
A bit about each. Enthuware lets me measure my progress with practice exams. CodingBat gets me writing puzzle solutions and exploiting properties of the API. Practice-It forces me to write complete code with a main method. JavaRanch gives me a sense of community and lets me see what my peers are doing (often saving me lengthy decision making sessions). I'm doing all this to get Oracle Certified because employers prefer something showing them I can write code.
I am never quite sure about coding bat (formerly called javabat). It is very good for trying out algorithms; my experience is that I can put an algorithm which I think is perfect and have coding bat find an example which breaks it. But having to write everything in the main method doesn't constitute object‑oriented programming.
Campbell Ritchie wrote:But having to write everything in the main method doesn't constitute object‑oriented programming.
I agree. Practice-It does allow me to make concrete classes and constructors, but it's not truly object oriented. CodingBat is also just java algorithm stubs. I use the two sites as tools to get me comfortable writing lines of code and solving code puzzles.
1) Core Java concepts
2) Web development concepts - MVC, RESTful web service, HTTP paradigms & stateless protocol
3) Spring & Hibernate concepts
4) 16 technical key areas like concurrency, memory management, performance, scalability, etc.