Core Java Basics

1. What are the key features of Java?
2. Explain the concept of JVM, JRE, and JDK.
3. What is the difference between == and .equals() in Java?
4. Explain the concept of final, finally, and finalize.
5. What is the difference between String, StringBuilder, and StringBuffer?
6. What are Java's access modifiers, and how do they work?
7. Explain the concept of overloading and overriding in Java.
8. What is the difference between static and instance methods?
9. How does Java achieve platform independence?
10. What is the difference between abstract classes and interfaces?

Object-Oriented Programming (OOP)

1. What are the four pillars of OOP in Java?
2. Explain the difference between composition and inheritance.
3. What is polymorphism? Provide examples.
4. How does encapsulation improve code security?
5. Can you explain the concept of multiple inheritance in Java?