1
拋出IOException並且出於某種原因無法捕獲。看看下面的代碼。堆棧跟蹤說調用「apply」方法時拋出IOException。然而，這個例外並沒有被catch子句捕捉到。當我嘗試去捕捉IOException時，Eclipse會抱怨說：「IOException的無法到達catch塊，這個異常永遠不會從try語句體中拋出」無法捕捉到IOException
爲什麼會發生這種情況？
代碼：
try {
action.apply();
}
catch (Exception e) {
System.out.println("Fail");
}
這裏的堆棧跟蹤：
java.io.IOException: Unable to download JavaScript from 'somesite' (status 404).
at com.gargoylesoftware.htmlunit.html.HtmlPage.loadJavaScriptFromUrl(HtmlPage.java:1023)
at com.gargoylesoftware.htmlunit.html.HtmlPage.loadExternalJavaScriptFile(HtmlPage.java:967)
at com.gargoylesoftware.htmlunit.html.HtmlScript.executeScriptIfNeeded(HtmlScript.java:353)
at com.gargoylesoftware.htmlunit.html.HtmlScript$1.execute(HtmlScript.java:225)
at com.gargoylesoftware.htmlunit.html.HtmlScript.onAllChildrenAddedToPage(HtmlScript.java:235)
at com.gargoylesoftware.htmlunit.html.HTMLParser$HtmlUnitDOMBuilder.endElement(HTMLParser.java:718)
at org.apache.xerces.parsers.AbstractSAXParser.endElement(Unknown Source)
at com.gargoylesoftware.htmlunit.html.HTMLParser$HtmlUnitDOMBuilder.endElement(HTMLParser.java:676)
at org.cyberneko.html.HTMLTagBalancer.callEndElement(HTMLTagBalancer.java:1136)
at org.cyberneko.html.HTMLTagBalancer.endElement(HTMLTagBalancer.java:1038)
at org.cyberneko.html.filters.DefaultFilter.endElement(DefaultFilter.java:206)
at org.cyberneko.html.filters.NamespaceBinder.endElement(NamespaceBinder.java:329)
at org.cyberneko.html.HTMLScanner$ContentScanner.scanEndElement(HTMLScanner.java:2999)
at org.cyberneko.html.HTMLScanner$ContentScanner.scan(HTMLScanner.java:1991)
at org.cyberneko.html.HTMLScanner.scanDocument(HTMLScanner.java:895)
at org.cyberneko.html.HTMLConfiguration.parse(HTMLConfiguration.java:499)
at org.cyberneko.html.HTMLConfiguration.parse(HTMLConfiguration.java:452)
at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
at com.gargoylesoftware.htmlunit.html.HTMLParser$HtmlUnitDOMBuilder.parse(HTMLParser.java:896)
at com.gargoylesoftware.htmlunit.html.HTMLParser.parse(HTMLParser.java:350)
at com.gargoylesoftware.htmlunit.html.HTMLParser.parseHtml(HTMLParser.java:304)
at com.gargoylesoftware.htmlunit.DefaultPageCreator.createHtmlPage(DefaultPageCreator.java:134)
at com.gargoylesoftware.htmlunit.DefaultPageCreator.createPage(DefaultPageCreator.java:101)
at com.gargoylesoftware.htmlunit.WebClient.loadWebResponseInto(WebClient.java:420)
at com.gargoylesoftware.htmlunit.WebClient.getPage(WebClient.java:303)
at com.gargoylesoftware.htmlunit.WebClient.getPage(WebClient.java:360)
at org.openqa.selenium.htmlunit.HtmlUnitDriver.get(HtmlUnitDriver.java:228)
at org.openqa.selenium.htmlunit.HtmlUnitDriver.get(HtmlUnitDriver.java:216)
at org.openqa.selenium.internal.seleniumemulation.Open.handleSeleneseCommand(Open.java:36)
at org.openqa.selenium.internal.seleniumemulation.Open.handleSeleneseCommand(Open.java:22)
at org.openqa.selenium.internal.seleniumemulation.SeleneseCommand.apply(SeleneseCommand.java:33)
at Action.runSeleniumAction(Action.java:235)
at SessionDriver.runSession(SessionDriver.java:192)
at SessionDriver.run(SessionDriver.java:123)