KStream and KTable concepts in Kafka - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a KStream from the topic 'input-topic'.

Kafka

KStream<String, String> stream = builder.stream([1]);

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Atopic("input-topic")

Binput-topic

Cstream("input-topic")

D"input-topic"

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to put quotes around the topic name.

Passing a variable without quotes.

Using incorrect method names.

The stream() method expects the topic name as a string in quotes.

2fill in blank

medium

Complete the code to create a KTable from the topic 'users'.

Kafka

KTable<String, String> table = builder.table([1]);

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Atopic("users")

Busers

C"users"

Dtable("users")

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the topic name without quotes.

Using incorrect method calls inside the argument.

The table() method requires the topic name as a string literal.

3fill in blank

hard

Fix the error in the code to convert a KStream to a KTable.

Kafka

KTable<String, String> table = stream.[1]();

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AtoStream

BtoTable

CtoKTable

DasTable

Attempts:

3 left

💡 Hint

Common Mistakes

Using toStream() which converts to a stream, not a table.

Using non-existent methods like toKTable() or asTable().

The correct method to convert a KStream to a KTable is toTable().

4fill in blank

hard

Fill both blanks to filter a KStream for values greater than 100 and map keys to uppercase.

Kafka

KStream<String, Integer> filtered = stream.filter((key, value) -> value [1] 100).mapKeys((key, value) -> key.[2]());

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A>

B<

CtoUpperCase

DtoLowerCase

Attempts:

3 left

💡 Hint

Common Mistakes

Using less than symbol instead of greater than.

Using toLowerCase() instead of toUpperCase().

We filter values greater than 100 using > and convert keys to uppercase with toUpperCase().

5fill in blank

hard

Fill all three blanks to create a KTable from a topic, filter entries with values not null, and map values to their length.

Kafka

KTable<String, Integer> result = builder.table([1]).filter((key, value) -> value [2] null).mapValues(value -> value.[3]());

Drag options to blanks, or click blank then click option'

A"events"

B!=

Clength

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using equality operator instead of not equal.

Forgetting quotes around the topic name.

Using incorrect method names for string length.

The topic name is a string "events". We filter values not equal to null using != and get the length of the value string with length().