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.

The '==' operator compares memory addresses of objects, while the .equals() method compares the content or value of objects.

• Use '==' for comparing memory addresses of objects.

• Use .equals() for comparing the content or value of objects.

• Example: String str1 = new String("hello"); String str2 = new String("hello"); str1 == str2 will return false, but str1.equals(str2) will return true.

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

A prime number is a number greater than 1 that can only be divided by 1 and itself.

• Prime numbers are integers greater than 1

• They have only two factors: 1 and the number itself

• Examples of prime numbers: 2, 3, 5, 7, 11, 13

The final keyword in Java is used to restrict the user from changing the value of a variable, making a method not overrideable, or preventing a class from being subclassed.

• Final variables cannot be reassigned once initialized

• Final methods cannot be overridden in subclasses

• Final classes cannot be subclassed

• Final parameters in a method cannot be modified within the method