Stock Price Tracker Java, API

```java
import java.io.IOException;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import com.google.gson.Gson;
import com.google.gson.JsonObject;
import java.util.Scanner;

public class StockPriceTracker {

    private static final String API_KEY = "YOUR_API_KEY"; // Replace with your API key
    private static final String API_URL = "https://www.alphavantage.co/query?function=GLOBAL_QUOTE&symbol=%s&apikey=%s";

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        while (true) {
            System.out.print("Enter stock symbol (or 'exit' to quit): ");
            String symbol = scanner.nextLine().toUpperCase();

            if (symbol.equalsIgnoreCase("exit")) {
                break;
            }

            try {
                double price = getStockPrice(symbol);
                System.out.println("Current price of " + symbol + ": " + price);
            } catch (IOException | InterruptedException e) {
                System.err.println("Error fetching stock price for " + symbol + ": " + e.getMessage());
            }
        }

        System.out.println("Exiting Stock Price Tracker.");
        scanner.close();
    }

    public static double getStockPrice(String symbol) throws IOException, InterruptedException {
        String url = String.format(API_URL, symbol, API_KEY);

        HttpClient client = HttpClient.newHttpClient();
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create(url))
                .build();

        HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());

        if (response.statusCode() != 200) {
            throw new IOException("API request failed with status code: " + response.statusCode());
        }

        String responseBody = response.body();
        //System.out.println("API Response: " + responseBody); //For debugging

        Gson gson = new Gson();
        JsonObject jsonObject = gson.fromJson(responseBody, JsonObject.class);


        if (jsonObject != null && jsonObject.has("Global Quote")) {
            JsonObject globalQuote = jsonObject.getAsJsonObject("Global Quote");
            if (globalQuote != null && globalQuote.has("05. price")) {
                String priceString = globalQuote.get("05. price").getAsString();
                try {
                  return Double.parseDouble(priceString);
                } catch (NumberFormatException e) {
                  throw new IOException("Invalid price format received from API: " + priceString);
                }

            } else {
                throw new IOException("Price data not found in API response for " + symbol);
            }
        } else {
            throw new IOException("Global Quote data not found in API response for " + symbol);
        }
    }
}
```