Reduce network calls in a Java applications

Reducing network calls in a Java application can help improve performance, reduce latency, and save bandwidth. Here are some ways to achieve this:

1. Use caching: Instead of making a network call every time you need data, consider caching it locally. This can be done using in-memory caching, disk caching, or using a distributed cache like Redis. This can help reduce the number of network calls required and improve application performance.

Caching

Suppose you have a web application that retrieves data from an API. Instead of making a network call every time the user accesses the page, you could cache the data in memory for a certain period of time. For example, you could use the Guava cache library to cache the data for 5 minutes:

Cache<String, String> cache = CacheBuilder.newBuilder()
        .expireAfterWrite(5, TimeUnit.MINUTES)
        .build();

String key = "some-api-endpoint";
String value = cache.get(key, () -> {
    // Make network call to API and return data
    return fetchDataFromApi(key);
});

2. Batch network calls: If your application makes multiple network calls for small amounts of data, consider batching these calls into a single call. This can help reduce the number of round trips between the client and server and improve network efficiency.

Batch network calls

Suppose your application needs to fetch data from multiple endpoints. Instead of making separate network calls to each endpoint, you could batch these calls into a single call. For example, you could use the Spring WebClient to make multiple parallel calls and then merge the results:

Flux<String> endpoint1 = webClient.get().uri("/endpoint1").retrieve().bodyToMono(String.class);
Flux<String> endpoint2 = webClient.get().uri("/endpoint2").retrieve().bodyToMono(String.class);

Flux<String> result = Flux.zip(endpoint1, endpoint2, (res1, res2) -> res1 + " " + res2);

3. Use compression: Compressing data before sending it over the network can help reduce the amount of data transmitted, thereby reducing network traffic. Java supports various compression algorithms such as gzip and deflate.

Compression

Suppose your application needs to transfer large files over the network. You could compress the files before sending them to reduce the amount of data transmitted. For example, you could use the GZIPOutputStream to compress the file before sending it:

Path file = Paths.get("path/to/file");
try (InputStream in = Files.newInputStream(file);
     OutputStream out = new GZIPOutputStream(Files.newOutputStream(file.resolveSibling(file.getFileName() + ".gz")))) {
    byte[] buffer = new byte[1024];
    int len;
    while ((len = in.read(buffer)) > 0) {
        out.write(buffer, 0, len);
    }
}

4. Use asynchronous calls: Asynchronous calls allow the application to continue executing while the network call is in progress. This can help reduce the amount of time the application spends waiting for the network call to complete.

asynchronous calls

Suppose your application needs to make a long-running network call. You could make the call asynchronously so that the application can continue executing while the call is in progress. For example, you could use the CompletableFuture class to make the call and then perform some processing on the result:

CompletableFuture<String> futureResult = CompletableFuture.supplyAsync(() -> {
    // Make long-running network call
    return fetchDataFromApi();
});

// Perform some processing on the result when it becomes available
futureResult.thenAccept(result -> {
    // Process result
});

5. Optimize database queries: If your application uses a database, optimize your queries to minimize the amount of data retrieved. This can help reduce the amount of data transmitted over the network.

Optimize database queries

Suppose your application needs to retrieve data from a database. You could optimize your queries to minimize the amount of data retrieved. For example, you could use a SELECT statement with a WHERE clause to retrieve only the data you need:

try (Connection conn = DriverManager.getConnection(url, username, password);
     Statement stmt = conn.createStatement();
     ResultSet rs = stmt.executeQuery("SELECT id, name FROM users WHERE age > 18")) {
    while (rs.next()) {
        int id = rs.getInt("id");
        String name = rs.getString("name");
        // Process data
    }
}

6. Minimize unnecessary calls: Review your code and identify any unnecessary network calls. Remove any calls that are not required, such as redundant calls or calls that are not used.

Suppose you have a web application that displays a list of products retrieved from an API endpoint. The API returns the list of products along with their availability status. You want to display an “In Stock” or “Out of Stock” message for each product based on its availability status.

One approach to implement this functionality would be to make a network call for each product to retrieve its availability status. However, this approach would result in multiple unnecessary network calls if the availability status of some products is already known.

To minimize unnecessary network calls, you could maintain a cache of product availability status in the client-side. Before making a network call to retrieve the availability status of a product, you could first check if the status is already available in the cache.

This is how this could be implemented:

Map<String, Boolean> productAvailabilityCache = new HashMap<>();

public boolean isProductInStock(String productId) {
    if (productAvailabilityCache.containsKey(productId)) {
        return productAvailabilityCache.get(productId);
    } else {
        boolean isProductInStock = fetchProductAvailability(productId);
        productAvailabilityCache.put(productId, isProductInStock);
        return isProductInStock;
    }
}

private boolean fetchProductAvailability(String productId) {
    // Make network call to retrieve product availability status
    // ...
}

In this example, the isProductInStock() method first checks if the availability status of the product is already available in the cache. If it is, it returns the cached value. Otherwise, it makes a network call to retrieve the availability status of the product, caches the value, and returns it.

By maintaining a cache of product availability status, unnecessary network calls can be avoided, resulting in better application performance and reduced network traffic.

By implementing these strategies, you can reduce the number of network calls in your Java application, improve performance, and optimize network usage.

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