Lambda expression

What are lambda expressions in java?

• lambda functions are similar to methods
• The difference is that they can be created in the methods body and arguments and they don't need a name

Advantages of lambda expressions

1. we can assign them as values
2. pass them in as arguments
3. return lambda from methods

Syntax

1. The simplest way to create a lambda expression which contain 1 parameter and an expression is

• parameter -> expression

eg. x -> x * x (will return you the square of the the argument) similar to int square(int x) { return x * x; }

• If there is no parameter the syntax will be () -> expression

2. If you have more than 1 parameter use parenthesis to contain them

(para1, para2) -> expression

• note within the parenthesis it can contain more than 2 parameter

3. There are limitations to expressions

• They have to return a value immediately
• cannot create variables in it
• cannot have assignments
• no if else statements
• no for/while loops

To overcome this limitations we wrap the code using curly braces {}.

• (para1, para2) -> {code}

eg. (Integer i, Interger j) -> {return j-i}

• note within the code if the method return a value or object there must be a return statement