Overview of the Best Java Web Scraping Libraries

There are many programming languages out there. Almost any of them can be used for web scraping: Java, Python, Go, C#, etc. The question is about personal preferences and the set of existing libraries and frameworks, as these are often used for a quick start – speeding up the development of application programs.

This article is not about choosing the best platform for development but about a specific language: Java. More precisely, it is about the most popular libraries that help create your own web parsers in Java.

Why Java Is a Popular Choice for Web Scraping

First of all, Java is one of the first cross-platform programming languages. Thanks to Java Virtual Machines, Java programming code can be run on almost any operating system. Everyone should remember games on feature phones. Well, they were written in Java.

Secondly, Java is a very popular language. It performs well and excels at working with complex logic.

Thirdly, Java offers many ready-made libraries and frameworks for parsing HTML and XML documents.

Fourthly, let's not forget about multithreading. Java is fully equipped in this area. It ensures efficient task distribution between multiple threads simultaneously and significantly speeds up the data collection process from many pages or websites.

Overview of Popular Java Web Scraping Libraries

Libraries are the sets of ready-made classes and methods designed for specific tasks. Since Java is used in various fields, many specialized libraries are available for Java web scraping and other different purposes.

Below, we highlighted the most relevant libraries for creating web parsers. Let's start with the most popular and almost indispensable Java scraping library – Jsoup, which is similar to Python's BeautifulSoup.

Jsoup

Jsoup is an open-source Java library designed for parsing HTML structures. HTML is the code returned in response to any HTTP/HTTPS request. Just as a reminder, HTTP stands for HyperText Transfer Protocol. Since Jsoup supports the current WHATWG HTML5 specification, it allows you to fetch and render the page code in the same way modern browsers do (which also works with this specification).

The library has been in development since 2009. With Jsoup, you can fetch HTML content from specific URLs or files, extract data based on HTML tags and CSS selectors, set your own attributes, navigate through pages, fill and submit forms, etc. Jsoup has a well-documented API.

Advantages:

• Open-source with regular updates.
• Supports the WHATWG HTML5 specification (like modern browsers).
• Simple syntax for Java web scraping.
• Supports XML and ASCII.
• Detailed documentation and a collection of recipes for common tasks.
• Built-in cleaner for checking and cleaning unsafe files/HTML code.
• An extensive set of methods for all situations (parsing API, working with DOM structure, CSS selectors).
• Minimal size (less than 1 MB).
• An online version of the library for testing.
• Completely self-contained and has no dependencies.
• Works with Java 8 and later versions.
• Proxy support.

Disadvantages:

• A large number of methods might require significant time to learn.
• Jsoup cannot handle dynamic sites as it only analyzes static HTML pages.
• Performance may degrade when working with large documents or frequent DOM-tree searches.
• Although the library supports basic CSS selectors, it doesn't cover all the features of modern selectors, such as pseudo-classes.

Code Example:

// Import librariesimport org.jsoup.Jsoup;import org.jsoup.nodes.Document;import org.jsoup.nodes.Element;import org.jsoup.select.Elements;import java.io.IOException;// A simple sample of Wikipedia parsing, starting with the class creationpublic class Wikipedia {public static void main(String[] args) throws IOException {// Create the document and fill it with content from Wikipedia homepageDocument doc = Jsoup.connect("http://en.wikipedia.org/").get();// Output the titlelog(doc.title());// Get the list of news headlinesElements newsHeadlines = doc.select("#mp-itn b a");for (Element headline : newsHeadlines) {// Collect titles and linkslog("%s\n\t%s", headline.attr("title"), headline.absUrl("href"));}}// Print the logprivate static void log(String msg, String... vals) {System.out.println(String.format(msg, vals));}}

Here is what an example of code parsing through the proxy may look like:

URL url = new URL("http://www.your-taget-site.com/");// proxy connection detailsProxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress("127.0.0.1", 8080));// open the connectionHttpURLConnection uc = (HttpURLConnection)url.openConnection(proxy);hc.setRequestProperty("User-Agent", " Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 YaBrowser/24.10.0.0 Safari/537.36");uc.setRequestProperty("Content-Language", "en-EN");uc.setRequestMethod("GET");uc.connect();// Create the document and proceed with the parsing logicDocument doc = Jsoup.parse(uc.getInputStream());…

HtmlUnit

This is a self-sufficient headless browser initially written in Java to be cross-platform and easily integrated with other scripts and programs written in Java. However, thanks to its high-level API, it can also work with other programming languages. Unlike more popular headless browsers, it does not have a graphical interface. However, it consumes minimal resources and provides the fastest site processing.

It can handle JavaScript, Ajax, and cookies, supports the HTTPS protocol, forms submissions, and effectively emulates user behavior. Development has been ongoing since 2002. The code is open source under the Apache 2.0 license. The library is ideal for automating tests (in web development) and content scraping.

Advantages:

• High-level API and cross-platform compatibility (via Java Virtual Machines).
• Ability to simulate any real browser (Chrome, Edge, Firefox, etc.).
• JavaScript (dynamic sites) and Ajax processing.
• File downloading and data submission via forms are supported. All standard HTTP methods (POST, GET, DELETE, HEAD, etc.) are supported.
• Cookie handling.
• The library is ported to .NET and has a special version for integration with Android applications.
• A ready-to-use web driver for integration with Selenium.
• Proxy support out of the box.
• Built-in HTML parser.

Disadvantages:

• JavaScript rendering is handled by a modified version of the Rhino engine (developed by Mozilla). This engine has many issues due to backward compatibility and is now outdated. Mozilla uses a different engine (SeaMonkey) in newer Firefox versions, so Rhino is no longer actively supported.
• HtmlUnit lacks a graphical interface, so you won't be able to detect rendering issues (for instance, font rendering problems, which can be used to block bots).
• It’s not possible to install plugins in this browser, which may be crucial for specific tasks.
• Unlike modern browsers with a graphical interface, HtmlUnit does not use hardware acceleration for rendering. This can lead to significant delays when processing sites with many external JS scripts.

Code Example

Here’s how the process of connecting via proxy with authentication may look like:

public void homePage_proxy() throws Exception {try (final WebClient webClient = new WebClient(BrowserVersion.CHROME, PROXY_HOST, PROXY_PORT)) {// The use of proxy with authenticationfinal DefaultCredentialsProvider credentialsProvider = (DefaultCredentialsProvider) webClient.getCredentialsProvider();credentialsProvider.addCredentials("login", "password", PROXY_HOST, PROXY_PORT);final HtmlPage page = webClient.getPage("https://target-domain.zone");Assert.assertEquals("Web page title", page.getTitleText());}}

Selenium

This is a suite of libraries and tools for automating almost any browser. Selenium acts as a middleware that organizes the API interface through special web drivers. Drivers are developed for all major browsers and platforms, including Firefox, Chrome, Safari, Edge, etc. It even supports the aforementioned HtmlUnit and integrates with most anti-detect browsers. Selenium works on all desktop operating systems: Windows, Linux, and macOS. A unique command language called Selenese was created for the original IDE system.

The project has existed since 2004. Currently, it offers web drivers, an IDE system, docker containers, and a system for managing many browsers (including those on remote servers) — Selenium Grid. Multiple programming languages, including Java, are supported.

Read also: Comparison of website testing tools (Selenium, Playwright, Puppeteer, Lighthouse).

Advantages:

• Remote control of real browsers (even if they do not have their own API interface).
• Since the site is loaded in a full browser, all code and scripts run correctly, including support for hardware acceleration.
• For Chrome, instead of a web driver, you can call the original API (DevTools Protocol, similar to the chromedp library).
• You can simulate user actions: move the pointer, fill in fields, submit and download files, click, etc.
• Comprehensive cross-platform compatibility and support for various programming languages.
• Ready-made solution for managing browsers on remote PCs/servers.
• Support for asynchronous requests and the ability to wait for certain elements on the page.
• Search for elements on the page and interact with them.
• The ability to take screenshots and create PDF versions of pages.

Disadvantages:

• Only five officially supported browsers: Chrome, Safari, Edge, Internet Explorer, and Firefox. Web drivers for others must be found separately (typically in GitHub repositories for the browsers themselves).
• The entry barrier is quite high. Not everyone can understand how to install and configure web drivers.
• The built-in parser syntax is weak, so for complex tasks, you need to use the syntax of other libraries and analyzers (XPath).

Code examples

Typical use of Selenium web driver for the Java parser:

package dev.selenium.hello;// Import librariesimport org.openqa.selenium.WebDriver;import org.openqa.selenium.chrome.ChromeDriver;// Launch a sample of headless browserpublic class HelloSelenium {public static void main(String[] args) {// Connect to Google ChromeWebDriver driver = new ChromeDriver();// Open the pagedriver.get("https://selenium.dev");// Close the browserdriver.quit();}}

And here is a sample of code to scrape text content from element:

// Find the first element with the H1 tag in the sample and copy its contentString text = driver.findElement(By.tagName("h1")).getText();System.out.println(text);

More examples of web scraping in Java can be found in the official repository.

Apache Nutch

This is a ready-made web parser written in Java, developed and maintained under the Apache team. It is positioned as an open-source web crawler. In some sources, it is referred to as a framework for building your own search engines (theoretically, you can create your own Google-like system). Nutch has a modular and extensible architecture, and the final project can run on a single machine or in a distributed environment like a Hadoop cluster. The collected data can be indexed by search engines like Elasticsearch and Apache Solr.

Mind, there was an attempt to develop Apache Nutch 2.0 intended to work with abstract data storage, but it was abandoned. Therefore, the first version is the most relevant and still actively developed.

Advantages:

• You get a ready-made Java parser that can be controlled from the command line.
• The parser can be extended and supplemented. There are both official and unofficial plugins.
• Parsing tasks can be created using regular expressions and large URL lists (you can crawl the entire Internet).
• The system can detect and remove duplicates automatically.
• Crawling results are stored in an indexed format, making it easier to search and export.
• Nutch can be installed on a server or in distributed clusters.
• Supports REST API. Ready-made Docker containers are available.
• Proxy support is available (you just need to correctly edit the configurations).
• Supports integration with the Selenium WebDriver.

Disadvantages:

• Nutch is quite complex to manage. You need to study the system's API beforehand. Everything is done via the console (there are no graphical interfaces).
• Installation and configuration are pretty complex, especially if you want to integrate the crawler with a local search engine.
• The built-in parser is incompatible with dynamic websites (written in JavaScript). Integration with Selenium must be manually configured.
• The codebase is huge, and using Nutch as a parser feels like using a cannon to shoot sparrows.

Code examples

If you manage to set up the essential environment, here’s what you need to do:

1. Change the crawler settings (configured in conf/nutch-site.xml).
2. Adjust the filters based on regular expressions (conf/regex-urlfilter.txt).
3. Add URL lists for crawling (create a folder urls/ and add a file seed.txt with addresses, each on a new line).
4. Run the crawler (a sample console command could look like this: bin/nutch crawl urls -dir crawl -depth 3 -topN 5).

If you wish, you can address nutch from your Java code:

import org.apache.hadoop.conf.Configuration;import org.apache.nutch.crawl.Crawl;import org.apache.nutch.fetcher.Fetcher;import org.apache.nutch.util.NutchConfiguration;public class NutchScraper {public static void main(String[] args) throws Exception {// Initiate Nutch sampleString url = "https://here.target.url/";// Create the configurationConfiguration conf = NutchConfiguration.create();Crawl nutch = new Crawl(conf);// Start crawling the URLnutch.crawl(url);Fetcher fetcher = new Fetcher(conf);fetcher.fetch(url);// Output the website Title in consoleSystem.out.println("Website title" + fetcher.getPage().getTitle());}}

WebMagic

This is another Java framework designed to accelerate the creation of custom parsers. Compared to Apache Nutch, it is much simpler both in implementation and configuration.

Advantages:

• Out-of-the-box support for multithreading.
• Easy integration with Selenium.
• Simple syntax for extracting data from websites — XPath and CSS selectors are supported.
• Extremely fast start and easy configuration.
• Ready-made examples for usage.
• Easy integration with your Java applications.
• Asynchronous operation out of the box.
• Convenient pipeline processing and customizable scheduler.

Disadvantages:

• The project is developed by essentially one developer, so updates are rare.
• Documentation is sparse, and there are very few subject-specific manuals available online.

Code examples

Here is an example of a Java parser code:

public static void main(String[] args) {Spider.create(new GithubRepoPageProcessor())// specify start URL.addUrl("https://target.url").addPipeline(new JsonFilePipeline("D:\\site-files\\"))// Open 2 threads.thread(2)// Launch the spider.run();}

Here is what a complete code for parser creation from official documentation may look like (parsing GitHub section):

import us.codecraft.webmagic.Page;import us.codecraft.webmagic.Site;import us.codecraft.webmagic.Spider;import us.codecraft.webmagic.processor.PageProcessor;// Create the processor with the entire critical logic and regular expressionspublic class GithubRepoPageProcessor implements PageProcessor {// Set retry attempts and sleep timeprivate Site site = Site.me().setRetryTimes(3).setSleepTime(100);@Overridepublic void process(Page page) {// Define the structure of requests - URL addresses and get the HTML codepage.addTargetRequests(page.getHtml().links().regex("(https://github\\.com/\\w+/\\w+)").all());// Create the “Author” fieldpage.putField("author", page.getUrl().regex("https://github\\.com/(\\w+)/.*").toString());// Define the “Name” field based on the H1 headerpage.putField("name", page.getHtml().xpath("//h1[@class='entry-title public']/strong/a/text()").toString());// If the name is blankif (page.getResultItems().get("name")==null){// Ignore the pages with blank namespage.setSkip(true);}// Define the readme filedpage.putField("readme", page.getHtml().xpath("//div[@id='readme']/tidyText()"));}@Overridepublic Site getSite() {return site;}// Launch the task and transfer it to the processor for parsing a particular website section in 5 threats public static void main(String[] args) {Spider.create(new GithubRepoPageProcessor()).addUrl("https://github.com/code4craft").thread(5).run();}}

Challenges and Limitations of Java Web Scraping

As mentioned earlier, Java works great for parser development. However, there are challenges you may encounter during the development process. Let’s outline the most significant limitations below:

• Java applications run in a specific environment—the Java Virtual Machine (JVM). This enables platform independence (detaching from the operating system), but it also imposes its own limitations and technical requirements. The JVM comes in many versions, each with unique technical features.
• Automatic memory management is beneficial for beginners, but memory leaks may occur when the amount of data processed by the script increases (a common scenario in Java scraping). To fix the error, you’ll have to completely overhaul the program's architecture. This is a task for experienced professionals. For instance, memory leaks are frequently observed in the HtmlUnit browser, caused by its rendering engine. To mitigate errors, it is recommended to disable the rendering engine in such cases.

• Java’s strict typing and specific requirements for integrating third-party modules or libraries may deter beginner developers. Diving into Java is more complex compared to languages like Python or Go.
• The number of pre-built libraries and frameworks for Java web scraping is not as extensive as for Python. Historically, Python has been more popular for data handling and scraping tasks.

Additionally, do not forget about the peculiarities of writing web parsers (as the software part)

• Many websites implement anti-bot measures to reduce server load. These measures involve checking multiple session and browser parameters. Therefore, it’s essential to pay close attention to HTTP headers and user agents and emulate other parameters. This requires niche knowledge and a deep understanding of web scraping Java.
• Some protection systems cannot be bypassed using solutions like HtmlUnit because they lack full-fledged hardware rendering. This results in structural mismatches and inconsistencies in the final document, which are exploited by website protection systems.
• JavaScript support also matters. Many modern websites come as complete web applications. If JavaScript is disabled in the browser, such sites may not work at all. Consequently, using headless browsers capable of hardware rendering is a must.

• Working with headless browsers involves significant resource consumption and additional delays. Therefore, implementing asynchronous processing in your scripts is crucial.
• Another problem is checking digital fingerprints. Bypassing such protection requires high-quality user action emulation, including realistic cookies, browsing history, and other parameters. In the multithreaded scraping, each "user" needs its unique fingerprint. Managing and processing many independent browser profiles requires robust anti-detection browsers.
• Many protection mechanisms are tied to client IP addresses. Thus, it makes sense to change IPs at a certain frequency or even with every new request. Using rotating proxies is recommended. The quality and type of IPs matter. Mobile and residential proxies are the most reliable for scraping.

Read Also: A Detailed Guide on Parsing Without Getting Blocked

Conclusion and Recommendations

The need to develop custom parsers arises for various reasons. Whatever these reasons are, simplifying an already complex task is always desirable. This is where specialized libraries and frameworks come into play.

Since Java is a widely used programming language, a sufficient number of ready-made solutions and libraries are available for it. The most popular and functional ones for Java web scraping have been listed above.

If you lack high-quality rotating proxies with global coverage to power your parser, consider Froxy. Our service provides access to over 10 million IP addresses, including mobile, residential, and server options. It offers targeting down to the city and telecom operator level. You only pay for the traffic used. The number of ports can be substantial - up to 1,000.