Northcorp Software Java Developer Interview Questions and Answers

JVM optimizes method calls using various techniques like inlining, escape analysis, and virtual method resolution.

• JVM can inline methods by replacing the method call with the actual code, reducing overhead.

• Escape analysis helps JVM determine if objects can be allocated on the stack instead of the heap.

• Virtual method resolution optimizes method calls by caching the resolved method to avoid repeated lookups.

HashMap is not thread-safe, while ConcurrentHashMap is designed for concurrent access, allowing safe multi-threaded operations.

• HashMap allows null keys and values; ConcurrentHashMap does not allow null keys or values.

• HashMap is not synchronized, making it unsuitable for multi-threaded environments.

• ConcurrentHashMap uses a lock striping technique, allowing multiple threads to read and write concurrently.

• Example: In...read more

Inheritance in JAVA allows a class to inherit properties and behaviors from another class.

• Allows a class to inherit fields and methods from another class

• Promotes code reusability and reduces redundancy

• Creates a parent-child relationship between classes

• Example: class B extends class A

In Java, a child class can acquire properties of its parent class using inheritance, allowing code reuse and polymorphism.

• Inheritance allows a subclass to inherit fields and methods from a superclass.

• Use the 'extends' keyword to create a subclass. Example: 'class Dog extends Animal {}'

• Access parent class properties using 'super' keyword. Example: 'super.methodName()'

• Override parent class methods in the child class...read more

Java program to check if a number is prime

• Create a function that takes an integer as input

• Check if the number is less than 2, return false

• Iterate from 2 to the square root of the number, check for divisibility

• If the number is divisible by any number, return false

• Otherwise, return true

JAVA is a high-level programming language known for its portability, security, and object-oriented features.

• JAVA is platform-independent, meaning it can run on any device with a Java Virtual Machine (JVM)

• It is object-oriented, allowing for modular and reusable code

• JAVA is known for its security features, such as sandboxing and encryption

• It is widely used for developing web applications, mobile apps, and enterprise...read more