Java Lambda Expressions
2 min readFeb 14, 2021
This article is a part of the Java Programming Language article series.
Lambda Expressions
- Treat functionality as method argument, or code as data
- For anonymous class implementations
- Looks a lot like a method declaration
- Consider as anonymous methods: methods without a name
Syntax of Lambda Expressions
A comma-separated list of parameters enclosed in parenthese
- Omit the data type of the parameters
- Omit the parentheses if there is only one parameter
The arrow token: ->
A body, which consists of a single expression or a statement block
- For a single expression, the Java runtime evaluates the expression and then returns its value
- A return statement can be used
- A return statement is not an expression, enclose statements in braces {}
- Do not have to enclose a void method invocation in braces
Functional Interface
- An interface that contains only one abstract method
- May contain one or more default methods or static methods
- Reduces the amount of code
- Standard functional interfaces: the java.util.function package
Approaches from Naive to Lambda Expressions
- Approach 1: A method that search one characteristic
- Approach 2: Using an anonymous class
- Approach 3: Using a lambda expression
- Approach 4: Using standard functional interfaces with lambda expressions
- Approach 5: Using lambda expressions with Consumer
- Approach 6: Using lambda expressions with Function
- Approach 7: Using generics
- Approach 8: Use Aggregate Operations That Accept Lambda Expressions as Parameters
Approach 1: A method that search one characteristic
Approach 2: Using an anonymous class
Approach 3: Using a lambda expression
Approach 4: Using standard functional interfaces with lambda expressions
Approach 5: Using lambda expressions with Consumer
Approach 6: Using lambda expressions with Function
Approach 7: Using generics
Approach 8: Use Aggregate Operations That Accept Lambda Expressions as Parameters
