This book is one of the THE MOST SIMPLE book for learning JAVA By:

exploiting how your brain works, Head First Java compresses the time it takes to learn and retain–complex information. Its unique approach not only shows you what you need to know about Java syntax, it teaches you to think like a Java programmer. If you want to be bored, buy some other book. But if you want to understand Java, this book’s for you. Head First Java is a complete learning experience in java and object oriented programming. This book helps you learn the Java Language with a unique methods that goes beyond syntrax and how to manuals and helps you understand how to be a great programmer.  you will learn language fundamentals, generics, threading, networking and distributed programming and you even build a sink the dot com game and networked drum machine chat client along the way.