Question

I am using htmlunit:

<dependency>
    <groupId>net.sourceforge.htmlunit</groupId>
    <artifactId>htmlunit</artifactId>
    <version>2.27</version>
</dependency>

I have simple loop which every one second print some data from response:

public static void main(String[] args) throws InterruptedException, IOException {

        WebClient webClient;

        webClient = new WebClient();

        webClient = new WebClient();
        webClient.getOptions().setThrowExceptionOnScriptError(false);
        final History window = webClient.getWebWindows().get(0).getHistory();
        final Field f;
        try {
            f = window.getClass().getDeclaredField("ignoreNewPages_"); //NoSuchFieldException
            f.setAccessible(true);
            ((ThreadLocal<Boolean>) f.get(window)).set(Boolean.TRUE);
        } catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException ex) {
            System.out.println(ex.getMessage());
        }

        for (int i = 0; i < Integer.MAX_VALUE; i++) {
            System.out.println(i);
            HtmlPage page = webClient.getPage("https://stackoverflow.com");
            System.out.println(page.getHead().toString());

            Thread.sleep(1000);

            webClient.getCookieManager().clearCookies();
            webClient.getCache().clear();

            final List<WebWindow> windows = webClient.getWebWindows();

            for (final WebWindow wd : windows) {

                wd.getJobManager().removeAllJobs();

            }

            webClient.close();

        }
    }

When I run the program, memory is growing, why? It is bug? Or what?

Answer 1

for (int i = 0; i < Integer.MAX_VALUE; i++) {
    System.out.println(i);
    HtmlPage page = webClient.getPage("https://stackoverflow.com");
    System.out.println(page.getHead().toString());

    Thread.sleep(1000);

    webClient.getCookieManager().clearCookies();
    webClient.getCache().clear();

    final List<WebWindow> windows = webClient.getWebWindows();

    for (final WebWindow wd : windows) {
        wd.getJobManager().removeAllJobs();
    }
}

根据上面的循环，它看起来你正在加载整个SOF主页Integer.MAX_VALUE次。当然，这会产生记忆效应。

Answer 2

有人检查过这段代码和jProfiler，似乎根本没有真正的内存泄漏。

public static void main(String[] args) throws Exception {
    for (int i = 0; i < Integer.MAX_VALUE; i++) {
        try (WebClient webClient = new WebClient()) {
            webClient.getOptions().setThrowExceptionOnScriptError(false);
            webClient.getOptions().setHistorySizeLimit(0);

            System.out.println(i);
            HtmlPage page = webClient.getPage("https://stackoverflow.com");
            System.out.println(page.getHead().toString());
        }

        Thread.sleep(1000);
    }
}

Memory leak in Htmlunit 2.27

2 个答案: