Error and Exception Handling

Question 1

What are Errors in Java?

Answer 1

Serious, unrecoverable issues often caused by runtime, hardware, or software failures. Examples:
OutOfMemoryError
StackOverflowError
VirtualMachineError

Question 2

What are Exceptions in Java?

Answer 2

Recoverable issues arising during program execution, such as:
NullPointerException
ArrayIndexOutOfBoundsException
FileNotFoundException

Question 3

Hierarchy of Errors and Exceptions?

Answer 3

Both inherit from the Throwable class, the root of the exception hierarchy.

Question 4

Difference Between Checked and Unchecked Exceptions?

Answer 4

Checked Exceptions:

External issues (e.g., file/network errors).
Must be handled using try-catch or declared with throws.
Examples: IOException, FileNotFoundException.
Unchecked Exceptions:

Programming errors (e.g., invalid arguments).
Handling not enforced by the compiler.
Examples: NullPointerException, ArithmeticException.

Question 5

Purpose of finally Block?

Answer 5

Executes crucial code (e.g., cleanup tasks) after try and catch, regardless of exceptions.