Managing random numbers

Generating a truly random number is a big topic that does not belong to this book. But for the vast majority of practical purposes, the pseudo-random number generators provided by Java are good enough, and that is what we are going to discuss in this section.

There are two primary ways to generate a random number in Java Standard Library:

• The java.lang.Math.random() method
• The java.util.Random class

There is also the java.security.SecureRandom class, which provides a cryptographically strong random number generator, but it is outside the scope of an introductory course.

Method java.lang.Math.random()

The static method double random() of the class Math returns a double type value greater than or equal to 0.0 and less than 1.0:

for(int i =0; i < 3; i++){
    System.out.println(Math.random());
//0.9350483840148613
    //0.0477353019234189
    //0.25784245516898985
}

We captured the result in the previous comments. But in practice, more often than not, a random integer from...