[Solved] Given the following Kafka Streams code snippet, what will be the output printed? var stream = builder.stream("orders"); var table = builder.table("orders"); stream.foreach((k, v) -> System.out.... | Kafka

Kafka - Streams

Given the following Kafka Streams code snippet, what will be the output printed?

var stream = builder.stream("orders");
var table = builder.table("orders");
stream.foreach((k, v) -> System.out.println("Stream: " + k + ":" + v));
table.toStream().foreach((k, v) -> System.out.println("Table: " + k + ":" + v));

Assuming the topic orders has these records in order: (1, "A"), (1, "B"), (2, "C").

AStream prints all three records; Table prints only latest for each key: (1, "B") and (2, "C")

BStream prints only latest record per key; Table prints all records

CBoth Stream and Table print all three records

DStream prints no records; Table prints all three records

Step-by-Step Solution

Solution:

Step 1: Understand KStream output
KStream processes every event as it arrives, so it prints all three records: Stream: 1:A, Stream: 1:B, Stream: 2:C.
Step 2: Understand KTable.toStream() output
KTable.toStream() emits the latest update per key. It will print updates for key 1 twice (first "A", then "B") and key 2 once ("C"). However, in practice, KTable.toStream() emits only the latest update per key, so the final output for the table stream will be (1, "B") and (2, "C").
Final Answer:
Stream prints all three records; Table prints only latest for each key: (1, "B") and (2, "C") -> Option A
Quick Check:
KStream emits all events; KTable.toStream() emits latest per key [OK]

Quick Trick: KStream prints all events; KTable.toStream() prints latest per key [OK]

Common Mistakes:

MISTAKES

Thinking KTable.toStream() prints all updates
Thinking KStream shows only latest per key
Confusing output order between stream and table

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More Kafka Quizzes

Given the following Kafka Streams code snippet, what will be the output printed?

Step 1: Understand KStream output

Step 2: Understand KTable.toStream() output

Final Answer:

Quick Check:

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