Content in Java:

1) JRE, JVM and JDK
2) Java Memory Management
3) Classes and Object
4) Constructor
5) Static Block 
6) Primitive data types
7) Object Oriented Programming Language

• Polymorphism
• Inheritance
• Encapsulation
• Abstraction

8) Interface

9) Abstract Class

10) Exception Handling

11) Collection Framework

• Set
• List
• Queue
• Map

12) Threads

13) Serilization

14) Wrapper Classes