Consider the following Kafka Streams processor code snippet:
medium📝 Debug Q7 of 15
Kafka - Advanced Stream Processing
Consider the following Kafka Streams processor code snippet:
public void init(ProcessorContext context) {
KeyValueStore store = context.getStateStore("myStore");
}
What is the main issue with this code?
AThe init method should not accept ProcessorContext as a parameter.
BThe state store name "myStore" must be registered before accessing it.
CThe returned object from getStateStore() must be cast to KeyValueStore<String, String>.
DState stores cannot be accessed inside the init method.
Step-by-Step Solution
Solution:
Step 1: Understand getStateStore() return type
The method context.getStateStore() returns a generic StateStore object.
Step 2: Casting requirement
To use it as a KeyValueStore, an explicit cast is required.
Step 3: Evaluate options
The returned object from getStateStore() must be cast to KeyValueStore. correctly identifies the missing cast. The state store name "myStore" must be registered before accessing it. is true but not the main issue here. Options C and D are incorrect.
Final Answer:
The returned object from getStateStore() must be cast to KeyValueStore<String, String>. -> Option C
Quick Check:
Cast getStateStore() result to specific store type [OK]
Quick Trick:Cast getStateStore() to correct store type [OK]
Common Mistakes:
Not casting the returned StateStore
Assuming state store is auto-typed
Trying to access store before registration
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