vishal2468/java8lambdabasics

Java Lambda is a paradigm shift from the traditional OOP that we are used to in Java.

• Understanding lambdas
• Using lambdas
• Functional interfaces
• Method references
• Collections improvements

Why Lambdas?

• Enables functional programming
• Readable and concise code
• Easier-to-use APIs and libraries
• Enables support for parallel processing

Why functional programming?

• Functional Programming does not lets you do anything that cant be already done using OOPs but It lets us write more maintainable code , readable code (same reason as we dont write in machine code).
• Its just an another tool in the toolbox.

Problems in OOPs

• Everything is an object
• All code blocks are "associated" with classes and objects

Write a code that can "perform any action". How to do that in Java using OOPs?

You made many many poor people. I realize of course it’s no shame to be poor, but it’s no great honor either. Now, what would be so terrible if I had a small fortune?

Similarly, There is no shame in writing a interface and then then passing the object of implementation class as an argument. But , what would have been so terrible if we could simply pass the behaviour as an argument.. Lambda sets out to achieve just that.
Inline Values ex. int a = 10;
So , is it possible to assign a block of code to a variable as a value?

blockOfCode={
    ...
    ...
}

aBlockOfCode = public void perform() {
System.out.print("Hello World!");
}

It makes sense to apply access specifier to a function only in context of a class.
We don't need the name either. We dont need to specify the return type.

aBlockOfCode =()->{
    System.out.print("Hello World!");
}

even more optimizations can me made

-> show how we can send inline function as an argument.
-> show examples of different lambda functions.

doubleNumber
addNumbers
safeDevide
stringLengthCount

Up-next:

-> next we see how to use lambda function in out code( also create a new interface and remove it)
-> we can also define a anonymous class.
-> compare the diff between anonymous , lambda and the implemented class.
-> show type inference using a new string length interface.
-> show example of java provided functional interfaces using thread.
-> also note that this tread class has been implemented long before java 8.

Functional Interface

Functional Interface has only one abstract method. It can have as many implemented methods , but only one abstract unimplemented methods.
@FunctionalInterface

Exercise1 do it without lambdas and with lambdas