This Java program is used to calculate the simple and compound interest for the given values of amount, rate and time.

Example:

```
import java.util .*;
class sici
{
public static void main (String argu[ ])
{
double pr, rate, t, sim,com;
Scanner sc=new Scanner (System. in);
System.out.println("Enter the amount:");
pr=sc.nextDouble();
System. out. println("Enter the No.of years:");
t=sc.nextDouble();
System. out. println("Enter the Rate of interest");
rate=sc.nextDouble();
sim=(pr * t * rate)/100;
com=pr * Math.pow(1.0+rate/100.0,t) - pr;
System.out.println("Simple Interest="+sim);
System.out. println("Compound Interest="+com);
}
}
```

Explanation:

First you have to import the *util package of Java* so that you can use the Scanner class in this program which will help programmers to fetch input from users. Then define a class name *sici*. Inside the class define the main() function. All Java program needs one main() function from where it starts executing program.

Next declare a double type variable name *pr*, *rate*, *t*, *sim* and *com*. Also define an object name **s** of Scanner class using which the value will be fetched from input device. Then System.out.println() method will be used to display a message - "Enter the amount:". Then the statement *pr=sc.nextDouble();* will be used to fetch the value from keyboard, and parse it to integer from string and store to variable *pr*. Similarly the values for time and rate will also be fetched from the user using *sc.nextDouble()*.

Now you have to use the formula for simple interest to calculate the SI with the given values. So the statement will be: *(pr * t * rate)/100;* which will get assigned to variable *sim*. Similarly the formula for compound interest is: *pr * Math.pow(1.0+rate/100.0,t) - pr;* and its calculated value will be assigned to variable *com*. The next two System.out.println() methods will be used to display the calculated result of simple and compound interest.