Given:javaObject input = 42;String result = switch (input) {case String s -> "It's a string...

Pattern Matching in switch

The switch expression introduced inJava 21supportspattern matchingfor different types.

However,a switch expression must be exhaustive, meaningit must cover all possible cases or provide a default case.

Why does compilation fail?

input is an Object, and the switch expression attempts to pattern-match it to String, Double, and Integer.

If input had been of another type (e.g., Float or Long), there would beno matching case, leading to anon-exhaustive switch.

Javarequires a default caseto ensure all possible inputs are covered.

Corrected Code (Adding a default Case)

java

Object input = 42;

String result = switch (input) {

case String s -> "It's a string with value: " + s;

case Double d -> "It's a double with value: " + d;

case Integer i -> "It's an integer with value: " + i;

default -> "Unknown type";

};

System.out.println(result);

With this change, the codecompiles and runs successfully.

Output:

vbnet

It's an integer with value: 42

Thus, the correct answer is:Compilation failsdue to a missing default case.

References:

Java SE 21 - Pattern Matching for switch

Java SE 21 - switch Expressions