CODEWITHSUNDEEP
javajava-8interfacedefault
ghostrider
ghostrider

Reputation: 2238

Why the use of "default" keyword in java8

In Java 8 default method implementation is introduced. My question is why the need to have default keyword in the method name/signature. Why can't it be without the default keyword just like a usual method implementation?

Upvotes: 0

Views: 2255

Answers (4)

user11595728
user11595728

Reputation:

It is worth noting that since Java 8 interfaces also support static methods. Leaving out the default keyword opens the door to ambiguity: would a method declaration in an interface that has no modifier be implicitly static (like constants), or implicitly default? As it is, everything is clear.

Upvotes: 3

PiRocks
PiRocks

Reputation: 2016

Note: This is speculation, but educated speculation. What @Kayaman's answer says is also likely true.

Java aims to be as backward compatible as possible. If you didn't include the default keyword then potentially invalid code, perhaps written by mistake, in a previous java version now compiles on Java 8+. This can be viewed as breaking backwards compatibility.

Upvotes: 0

Kayaman
Kayaman

Reputation: 73528

It makes the intention clear. You can't accidentally create a default implementation for a method. Just like abstract methods require the keyword, instead of just being methods without implementation.

A safety precaution for the careless programmers.

Upvotes: 8

Vetrivel Govindarasu
Vetrivel Govindarasu

Reputation: 1

In Java 8, “Default Method” or (Defender methods) feature, which allows the developer to add new methods to the interfaces without breaking their existing implementation. It provides the flexibility to allow interface to define implementation which will use as the default in a situation where a concrete class fails to provide an implementation for that method.

You can refer the below URL to understand more details. https://dzone.com/articles/interface-default-methods-java

Upvotes: -4

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