This Java program is used to demonstrates find largest and smallest number in an Array.

Example:

```
public class FindLargestSmallestNumber {
public static void main(String[] args) {
//numbers array
int numbers[] = new int[]{55,32,45,98,82,11,9,39,50};
//assign first element of an array to largest and smallest
int smallest = numbers[0];
int largetst = numbers[0];
for (int i = 1; i < numbers.length; i++) {
if (numbers[i] > largetst)
largetst = numbers[i];
else if (numbers[i] < smallest)
smallest = numbers[i];
}
System.out.println("Largest Number is : " + largetst);
System.out.println("Smallest Number is : " + smallest);
}
}
```

Program Output:

Explanation:

This Java program shows how to find the largest and the smallest number from within an array. Here in this program, a Java class name *FindLargestSmallestNumber* is declared which is having the main() method. Inside the main(), the integer type array is declared and initialized. The integer type array is used to store consecutive values all of them having type integer. The statement is:

int numbers[] = new int[]{55,32,45,98,82,11,9,39,50};

The numbers 55, 55, 32, 45, 98, 82, 11, 9, 39, 50 are stored manually by the programmer at the compile time. Then two integer type variable, name *smallest* and *largest* are declared and initialized with the *0 ^{th}* index value of the array.

Then a 'for loop' is used which goes from 1 to the array length. Within this loop the largest and the smallest value is detected and initialized to the smallest and largest value uisng if()

When …. numbers[i] is greater than largetst

largetst = numbers[i];

when numbers[i] greater than smallest

smallest = numbers[i];

The last two statements --

System.out.println("Largest Number is : " + largetst);

System.out.println("Smallest Number is : " + smallest);

Is used to print the largest and the smallest value which is extracted from the array.