Java Program For Armstrong Number 

public class Armstrong {
	public static void main(String[] args)
	{
		int n=153,r;
		int sum=0;
		int n1;
		n1=n;
		while(n!=0)
		{
			 r=n%10;
			 sum=sum + r*r*r;
			 n=n/10;
		}
		if (n1==sum)
			System.out.println("the given number is Armstrong");
		else
			System.out.println("the given number is not Armstrong");
	}
}

OUTPUT:

C:\java>javac Armstrong.java
C:\java>java Armstrong
the given number is Armstrong

Simple Java program for finding a number is Armstrong or not, here the value is predefined. The same program can be re written using functions by dynamically reading values.