- Java Keywords, Identifiers, Statics, Final, Abstract
- OOPS Concepts: Abstraction (Abstract Classes & Interfaces), Encapsulation (Getters, Setters), Inheritance (Hierarchies, Casting), Polymorphism (Overloading, Overriding)
- Operators
- Exceptions, Assertions
- Strings, Dates, I18N, Utilities
- IO and Serialization
- Collections& Generics
- Threads & Executor Framework
- Inner Classes
- Compilation and Execution process and Commandline commands
- JVM, Memory, Garbage Collection, Caching
- Reflection
- RMI, Networking, Socket Programming