In Java 8 why we cannot convert Math.random() to Math::random using method references

Question

This works

Supplier<Double> random1 = () -> Math.random();

Why this doesn't work:

Supplier<Double> random2 = () -> Math::random

Answer 1

Using just the method reference would work such as:

Supplier<Double> random2 = Math::random

since it already represents a Supplier<Double>.

On the other hand, the current notation that you've used would represent a Supplier of Supplier<Double> such as:

Supplier<Supplier<Double>> random2 = () -> Math::random;