code this in java using patterns: Specification: Read in integers until the user enters -1. If there was at least one integer, show the average value.

Sure, here is a simple Java program that reads integers from the user until they enter -1, then calculates and prints the average of the entered numbers.

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int sum = 0;
        int count = 0;
        int input;

        System.out.println("Enter integers. Enter -1 to stop.");

        while (true) {
            input = scanner.nextInt();
            if (input == -1) {
                break;
            }
            sum += input;
            count++;
        }

        if (count > 0) {
            double average = (double) sum / count;
            System.out.println("The average is: " + average);
        } else {
            System.out.println("No integers were entered.");
        }
    }
}

This program works as follows:

1. It first creates a Scanner object to read the user's input.
2. It then enters a loop where it reads an integer from the user.
3. If the user enters -1, it breaks out of the loop.
4. Otherwise, it adds the entered number to the sum and increments the count of numbers.
5. After the loop, if at least one number was entered (i.e., count > 0), it calculates the average by dividing the sum by the count and prints it.
6. If no numbers were entered, it prints a message saying so.