Functional Java with Streams & Lambdas

Explain functional interfaces and implement them using lambda expressions and method references.

Describe the key principles of the Stream API, including lazy evaluation and intermediate vs. terminal operations.

Solve data transformation problems using core stream operations like filter, map, and reduce.

Solve problems involving nested collections using the flatMap operation.

Group and partition collection data effectively using built-in collectors like groupingBy and partitioningBy.

Write idiomatic, null-safe code using the Optional class.

Analyze the performance trade-offs and potential pitfalls of using parallel streams.

Implement a custom collector for a specialized stream aggregation scenario.