Is there an easier way to declare a lambda as a variable in java similar to that of Kotlin?-CodePudding

here's how lambdas are in kotlin -

val myLambda: (Int, Int) -> Unit = { a, b ->
    Log.d(TAG, "sum value = ${a   b}")
}
myLambda(1, 2)//running the lambda

In java, I found these two methods to do the same.

Here, I can't have the runnable take a parameter.

// runnable method
Runnable runnable = () -> {
    System.out.println("x");
};
runnable.run();

The issue with this method is I would have to declare multiple interfaces for different types

// interface method
Finder finder = (s1, s2) -> s1.indexOf(s2);
System.out.println(finder.find("1234", "23"));

public interface Finder {
    public int find(String s1, String s2);
}

So, the question I have is whether there is an easier way to implement lambda in java better that both of these.
Note - I'm new to java.

CodePudding user response：

No. Java does not have function types built into the language. You must have an interface for every lambda you define.

...or you can use the built-in ones, which are sufficient for many use cases. This, for example, might be a ToIntBiFunction<String, String>.

CodePudding user response：

Since Java 8, there is the Generic Function interface. It allows you to store lambda functions.