[Solved] Why does the following code throw an exception at runtime?ReadOnlyKeyValueStore<String, String> store = streams.store("myStore", QueryableStoreTypes.keyValueStore()); String val = store.get(null); | Kafka

Kafka - Advanced Stream Processing

Why does the following code throw an exception at runtime?

ReadOnlyKeyValueStore<String, String> store = streams.store("myStore", QueryableStoreTypes.keyValueStore());
String val = store.get(null);

Astore.get() requires a non-empty string key

BNull keys are not allowed in state stores

Cstore.get() only accepts integer keys

DThe store was not initialized

Step-by-Step Solution

Solution:

Step 1: Understand key constraints in state stores
State stores do not allow null keys; passing null causes exceptions.
Step 2: Analyze the code behavior
Calling store.get(null) triggers an exception due to invalid key.
Final Answer:
Null keys are not allowed in state stores -> Option B
Quick Check:
Null keys cause exceptions in state stores [OK]

Quick Trick: Never pass null as key to store.get() [OK]

Common Mistakes:

Master "Advanced Stream Processing" in Kafka

9 interactive learning modes - each teaches the same concept differently

More Kafka Quizzes

Why does the following code throw an exception at runtime?