The Java Stream API has many useful methods. If we want to transform a Stream into a Java array, we can use the toArray method. Without an argument, the result is an object array ( Object[]), but we can also use an argument to return an array of another type. The easiest way is to use the contructor of the array type we want as a method reference. Then, the result is an array of the given type with the elements of the stream.
This is very useful if we have a Java Stream and want to use the elements to invoke a method with a variable arguments parameter. In Java, we can pass an array object as variable arguments argument to a method. So if we transform the Stream into an array we can invoke the method with that value.