Lambda expression syntax example

In Java, anonymous inner classes provide a way to implement classes that may occur only once in an application. Lambda expressions address the bulkiness of anonymous inner classes by converting five lines of code into a single statement. This simple horizontal solution solves the "vertical problem" presented by inner classes.

A lambda expression is composed of three parts.

The body can be either single expression or block of statements. In the expression form, the body is simply evaluated and returned. In the block form, the body is evaluated like a method body and a return statement returns control to the caller of the anonymous method. The break and continue keywords are illegal at the top level, but are permitted within loops. If the body produces a result, every control path must return something or throw an exception.

Here are few example syntaxes:

(int x, int y) -> x + y

() -> 90

(String str) -> {System.out.println(str);}

The first expression takes two arguments called x, y, and returns sum of x, y.

The second expression takes no argument, and returns an integer 90.

The third expression takes String as an argument. It contains a block to print the string. This block of code is not returning nothing.

Java-8 Lambda expression examples

1. Lambda expression syntax example
2. Lambda example with single method interface implementation.
3. Comparator example with Lambda implementation.
4. How to return lambda as an object?