java - Geb - IncompatibleClassChangeError

Question

I'm just starting out with Geb and am encountering this error when inputting sample code from the Book of Geb:

import geb.Browser


Browser.drive {
    go "http://google.com/ncr"

    // make sure we actually got to the page
    assert title == "Google"

    // enter wikipedia into the search field
    $("input", name: "q").value("wikipedia")

    // wait for the change to results page to happen
    // (google updates the page dynamically without a new request)
    waitFor { title.endsWith("Google Search") }

    // is the first link to wikipedia?
    def firstLink = $("li.g", 0).find("a.l")
    assert firstLink.text() == "Wikipedia"

    // click the link
    firstLink.click()

    // wait for Google's javascript to redirect to Wikipedia
    waitFor { title == "Wikipedia" }
}

I am encountering this exception:

Caught: java.lang.IncompatibleClassChangeError: the number of constructors during runtime and compile time for java.lang.Exception do not match. Expected 4 but got 5
    at geb.error.GebException.<init>(GebException.groovy:20)
    at geb.waiting.WaitTimeoutException.<init>(WaitTimeoutException.groovy:30)
    at geb.waiting.Wait.waitFor(Wait.groovy:108)
        .......

Any ideas? Thanks!

Answer 1

Are you using Java 7 by any chance? Groovy code that uses exceptions that was compiled with < Java 7 is not compatible with Java 7.