[KAFKA-4672] KIP-100 api changes break Java 8 lambda expressions in some cases

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.10.2.0
• Fix Version/s: 0.10.2.0, 0.11.0.0
• Component/s: streams
• Assignee: Xavier Léauté
• Reporter: Xavier Léauté
• Created: 18/Jan/17 23:40
• Updated: 22/Jan/17 01:10
• Resolved: 22/Jan/17 01:10

Description

Variance changes introduced in KIP-100 cause compilation failures with lambda expression in Java 8.

To my knowledge this only affects the following method
KStreams.transform(TransformerSupplier<...>, String...)

prior to the changes it was possible to write

streams.transform(MyTransformer::new)

where MyTransformer extends Transformer.

After the changes the Java compiler is unable to infer correct return types for the lambda expression.

Issue Links

• links to: GitHub Pull Request #2402