Java

CORE JAVA INTERVIEW QUESTIONS

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Curriculum

Topic

What is Java, and what makes it platform-independent (write once, run anywhere)2:00
Difference Between JDK, JRE, and JVM2:04
What is bytecode, and how does the JVM execute it Where does JIT fit in1:57
Why is the main() method declared public static void main(String[] args) — explain each keyword1:55
What is the difference between a compile-time error and a runtime error in Java1:53
What are the primitive data types in Java, and what is autoboxingunboxing2:33
08 - What is the difference between static and instance (non-static) members1:54
What are the four pillars of OOP (encapsulation, inheritance, polymorphism, abstraction)1:57
What is encapsulation, and how do getterssetters and private fields enforce it1:52
What is inheritance, and what does the super keyword do2:00
12 - What is polymorphism Explain compile-time vs runtime polymorphism2:03
12 - What is polymorphism Explain compile-time vs runtime polymorphism2:03
13 - What is the difference between method overloading and method overriding1:57
14 - What is abstraction, and what is the difference between an abstract class and an interface2:11
15 - Can an interface have method bodies Explain default and static methods in interfaces2:04
16 - What is a constructor Explain default, parameterized, and constructor chaining (this() super())1:55
17 - Why does Java not support multiple inheritance with classes, and how do interfaces solve it2:05
18 - What are the final, finally, and finalize() — and how do they differ2:06
19 - Why are Strings immutable in Java, and what benefits does immutability provide2:04
20 - What is the difference between String, StringBuilder, and StringBuffer2:03