pseudocode:

        initialize array with random numbers
        
       step 1: initilize smallestNumber and largestNumber point to zeroth index
       as smallestNumber = array[0]
        largestNumber = array[1]

       step 2: run array thruogh for loop()
       step 3: update smallestNumber and largestNumber in each loop
        like if array[i] > largest
        set largest to array[i]
        
        if array[i] < smallest
        set smallest to array[i]

       step 4:  print(smallest, largest)

// Java code for the same

package java_problems_datastructures;

public class SmallestAndLargestNumber {
    
    // Driver method
	public static void main(String args[]) {

        // declare an array
		int[] arrayOfIntegers = { 234, 34, 45, 243, 545,-89, 54, 890, 3434, 9, 9843, 5, 453 };
        // call the method
		smallestAndLargest(arrayOfIntegers);

	}

	private static void smallestAndLargest(int[] array) {
        // point both values to first index of the array
		long smallestNumber = array[0];
		long largestNumber = array[0];

		for (int i = 1; i < array.length; i++) {

            // if we find smaller/greater than that, update the variable
			if (array[i] <= smallestNumber)
				smallestNumber = array[i];
			else if (array[i] >= largestNumber)
				largestNumber = array[i];

		}
        // print both values
		System.out.print("smallest number is: " + smallestNumber + "\n");
		System.out.print("largest number is: " + largestNumber);

	}

}

Output:

smallest number is: -89
largest number is: 9843