I have been working in Java for more than 8-9 months now. I want to have deep understanding of Java concepts now. For ex: Collections properties, threading, interfaces detailed concepts etc. I mean I have been using all these things for a while now but want to know about the things of Java in detail. Can you suggest some online source/Java book or something like this which I can follow? Usually, I search on web whatever I want to study and read the top 3-4 links. But, some book or course will help me better. Thanks in advance.

Java How To Program

commented: Why pay $133 when there are free alternatives that are more authoritative -3

Josh Bloch's Effective Java (2nd edition) is a good read.

I think the second book is what you're looking for. It contains (collections properties, threading, interfaces detailed concepts) and it explains Java slowly, gradually and in a formal way.
1) Beginner - Head First Java
2) Intermediate - Java in a Nutshell 6th Edition by Benjamin J. Evans & David Flanagan
3) Advanced - Josh Bloch's Effective Java (2nd edition)

By the way if you want deep concepts I would also recommend you checking out Bruce Eckel's Thinking In Java.

@James It doesn't talk about collections, threading etc.

@Freshly, I tried to search pdf for second book but not able to find it somewhere.

Thanks for the valuable responses.

What search engine are you using? It's fairly new; it just came out early 2015 so you should be able to find it. Have you tried googling it? Try highlighting the title of the second book with your mouse, right click then select Search Google for "..." I actually found a pdf just now. Here's the link to it: Java in a Nutshell 6th Edition

commented: wow! Google seems to be biased for u :D +4

@James It doesn't talk about collections, threading etc.

??? The Oracle tutorials have huge sections on Colllections and on Threading - see the trails on Concurrency and Collections in the link I posted.

Thank you for sharing your experience; I hail to your 8 years of journey in Java Programing. I am a beginner in Java, however I researched a lot to gain understanding about Java development and concepts besides I found some free and paid tutorials and forum. Here are some interesting and outstanding support you may expect:
1. guru99.com (Completely Free)
2. Udemy.com
3. w3c.org (as you might familiar)
However, java.com is your best friend. Best of Luck!

@freshly, As I checked, we don't have much things for threading in the book you mentioned. did you mean something else?

Thanks in advance.