What Is a Lambda Expression

Description

A lambda expression is an unnamed function with parameters and a body.

The lambda expression body can be a block statement or an expression.

-> separates the parameters and the body.

Example

(int x) -> x + 1 takes an int parameter and returns the parameter value incremented by 1.

(int x, int y) -> x + y takes two int parameters and returns the sum.

(String msg)->{System.out.println(msg);} takes a String parameter and prints it on the standard output.

msg->System.out.println(msg) takes a parameter and prints it on the standard output. It is identical to the code above.

() -> "hi" takes no parameters and returns a string.

(String str) -> str.length() takes a String parameter and returns its length.

The following lambda takes two int parameters and returns the maximum of the two.

(int x, int y)  ->  {  
    int max = x  > y  ?  x  : y;
    return max;
}