How to instantiate a class in a Java .class using Visual Studio Code?

I am using Visual Studio Code (version 1.32.3) with Java. I have a .class file called 'RandomGenerator.class' which I want to instantiate from the main. The main.java and RandomGenerator.class are in the same directory.

My statement:

RandomGenerator rdgen = new RandomGenerator(1,1,1,1);

will have an error :RandomGenerator could not be resolved to a type java(16777218)

I tried to include import RandomGenerator; (I don't need but try to see if it is required) - I get an error "RandomGenerator cannot be resolved java(268435846)" at the import statement.

The specification of the constructor given is RandomGenerator​(int seed, double lambda, double mu, double rho)

Appreciate help to make it work in Visual Studio Code. Thanks.