Explain what unchecked exceptions are in programming

Unchecked exceptions are runtime exceptions in Java that do not require mandatory handling or declaration in the method signature (no need to write throws). They inherit from the RuntimeException class.

Main features of unchecked exceptions:

• They arise from programming errors, such as NullPointerException, ArrayIndexOutOfBoundsException.
• The compiler does not force handling or declaring them.
• Handling them is optional, and they often indicate logical errors that need fixing rather than just catching.

Example of an unchecked exception:

public void printLength(String s) {
    System.out.println(s.length()); // may throw NullPointerException
}

If s is null, an unchecked exception NullPointerException will be thrown.