Lambda Expressions -> Java

Identify a functional interface as an interface with one abstract method, and distinguish abstract from non-abstract methods, noting the optional functional interface annotation and its checks.

Explore Java functional interfaces and their single abstract method definitions, including callable and comparable, and learn how lambda expressions enable functional programming across Java versions.

Explore lambda expressions as anonymous, nameless functions, compare them with named methods that add two numbers, and learn the syntax, optional parameters, and converting methods to lambdas in Java 8.

Follow Java lambda expression rules: curly braces optional for single-line expressions, mandatory for multi-line or when using a return keyword, semicolon required; lambda expressions require a functional interface.

Learn how lambda expressions replace verbose interface implementations in Java 8, using the HelloInterface1 example to print hello with an anonymous function.

Debug a lambda expression in Java by tracing its flow from main to addTwoNumbers and into the anonymous lambda implementing sumOfTwoNumbers. The lambda prints inputs and returns their sum, 300.

Explore method references with the double colon ::, showing how static and non-static methods can be referenced as an alternative to lambda expressions.

Explore the for-each style in Java 8 to iterate and print a list of integers, comparing it with the traditional for loop for concise code.

Learn how default methods in interfaces provide a body that implementing classes inherit, preventing compilation errors when adding new methods, with Java 8 streams as an example.

Explore how static methods in interfaces provide reusable utility functionality in Java 8 and later, with bodies, accessed via the interface name, and not overridable by implementing classes.

Explore how to identify a functional interface in Java by examining abstract, default, and static methods, and how the Object class methods like equals affect the classification.

Explore Java 8's predefined functional interface Function, which takes one input and returns one output, using apply, with examples like currency conversion and square calculations.

Demonstrate chaining functions with andThen and compose on the predefined functional interface Function, showing input flowing through function1 and function2 to produce uppercased and appended results.

Demonstrate Java 8's predefined functional interface predicate, which takes an input and returns true or false. See an example checking transaction amounts above 10000, illustrating its use over custom logic.

Explore how the supplier predefined functional interface in Java 8 handles no-input value generation, allowing you to return an INR rate with supplier.get rather than a custom method.

Explore the predefined functional interface consumer in Java 8 onwards, which accepts a single input and returns nothing, demonstrated via consumer.accept and simple actions.