Sometimes, we have to create a system generated random number. You can do this in Java by using Math.random() method. This method returns a float value range between 0 - 1. i.e.; the value could be 0.12, 0.23, 0.45 etc.

If we need to generate a random value range between 0 - 100, we should multiply the above random values with 100 and round it to get an integer. So, the random values generated will be 12, 23, 45 and etc.

I've written a common method to generate a random value based on the range value given.

RandomTest.java

public class RandomTest
{
public static void main(String args[])
{
for(int i=1;i<=100;i++)
{
int n = randomValue(100);
System.out.println(n);
}
}
public static int randomValue(int range)
{
Double d = new Double(Math.random()*range);
int n = d.intValue()%range;
n = (n==0)?range:n;
return n;
}
}