Stabilize stream pipeline cleanup
Medium Java arena: Streams, collectors, grouping, and null-safe filtering
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Missing prerequisites: java-easy-stream-pipeline
A reporting endpoint uses loops that are hard to audit and easy to break. You are working inside a Java backend interview lab, and the arena only clears when the result is safe, deterministic, and explainable.
Learn to apply Streams, collectors, grouping, and null-safe filtering in a Java backend interview lab while explaining the invariant, safety constraints, and hidden edge cases.
- Demonstrates Streams, collectors, grouping, and null-safe filtering
- Handles the visible sample and hidden edge cases
- Keeps output deterministic and explainable
- Avoids unsafe dynamic execution
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