Lambdas in Java(1.8) - 1

Lambdas

reference :https://www.youtube.com/watch?v=gpIUfj3KaOc

They are a concept of passing a method definition itself in a very short form over passing and argument using a method definition.
In other words, A piece of code gets assigned to a method itself (a block of code) .
Something like :

• aBlockofCode = public void perform(){System.out.print("Hello");}... All Lambda expressions are in orange text below:

However, with the right syntax:

• Ex 1: aBlockofCode= () -> {System.out.print("Hello");}

• the bolded expression is a lambda expression.
• //note that  ";" is within the curly braces
• The braces is not requires if the block of code contains only one statement.

• Ex 2: aBlockofCode= (int a) -> a*2;//here, the functions takes a param int a, and returns (a*2). The statement "return" is ignored here, since blocking(using curly braces for multiple statments) is not required. However, if block of code, return needs to be defnied wenevr required.
• Ex 3: aBlockofCode=  (int a,int b) -> { 

if(b==0) return 0; 

return a/b;

};

• Ex 4: aBlockofCode= (String s) -> s.length();

While the orange text is referring a lambda expression, a lambda expression can be defined as a interface. Refer the examples below for more understanding:

public class Lambdas {

public static void main(String[] args) {

PrintHalloLambdaInterface halloVarLambda = ()->System.out.println("hello");// --(A)

halloVarLambda.PrintHalloMethod();

AddParamsLambdaInterface addParams = (int a, int b)->a+b;// --(B)

System.out.println(addParams.PrintSum(2, 3));

StringLengthLambdaInterface strLenLambda =(String s)->s.length();// --(C)

System.out.println(strLenLambda.PrintStrLength("StringLength"));

}

interface PrintHalloLambdaInterface{

 void PrintHalloMethod(); //param not taken or returns- implemented body in//  --(A)

}

interface AddParamsLambdaInterface{

 int PrintSum(int a, int b);//2 int params taken and returns an int- implemented body in // --(B)

}

interface StringLengthLambdaInterface{

 int PrintStrLength(String str);

}

}

Note:

• TYPE INFERENCE - Replacing "String s" with just "s" is valid in --(C)
• StringLengthLambdaInterface strLenLambda = s ->s.length();// --(C)
• A LambdaInterface can have only one abstract method(Functional Interface) that matches the lambda