Stream.generate()

 Stream.generate() uses a given supplier (a function without arguments) to produce an infinite stream of values. Unlike iterate(), each new element is produced independently rather than based on the previous element.

1 . Generating a Constant Value

In this example, we create a stream that repeatedly outputs the same string. We then limit the stream so that only five copies are printed

import java.util.stream.Stream;

public class GenerateBasicExample {

    public static void main(String[] args) {

        // Generate a stream where each element is "Hello Java".

        Stream<String> constantStream = Stream.generate(() -> "Hello Java");

        

        // Limit the stream to 5 elements and print them.

        constantStream.limit(5).forEach(System.out::println);

    }

}

Explanation: The supplier (() -> "Hello Java") is called repeatedly to produce each element in the stream. The stream would be infinite if not for limit(5).

Output::

Hello Java

Hello Java

Hello Java

Hello Java

Hello Java

2 .

Generating Random Numbers

This example makes use of the built-in Math.random() method as a supplier to generate random numbers. Again, we limit the stream so it outputs a finite number of elements.

import java.util.stream.Stream;

public class RandomNumbersGenerate {

    public static void main(String[] args) {

        // Generate an infinite stream of random double values.

        Stream<Double> randomNumbers = Stream.generate(Math::random);

        

        // Limit to 5 random numbers and print each.

        randomNumbers.limit(5).forEach(System.out::println);

    }

}

Explanation: Math::random is a method reference that supplies a new random double (between 0.0 and 1.0) each time it is called. The stream is limited to 5 elements.

Output: The output will be 5 random double numbers, for example:

0.23744893145251387

0.8912345123451234

0.11234567890123456

0.6734523981274352

0.5493827459812739