java | 易学教程

-XX:OnOutOfMemoryError doesn't work for java.lang.OutOfMemoryError: unable to create new native thread

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问题 I use -XX:OnOutOfMemoryError=\"kill -9 %p\". It works for most of out of memory cases, but it doesn't kill the process for java.lang.OutOfMemoryError: unable to create new native thread. 回答1: It may well be that the system cannot handle any more threads. That, unfortunately, would also mean that no new processes can be created - but the kill command would run as a new process! A rather unpleasant Catch-22... 来源： https://stackoverflow.com/questions/23373117/xxonoutofmemoryerror-doesnt-work-for

Unable to detect Alert using ChromeDriver?

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问题 I am currently doing some automation testing using Selenium WebDriver . The issue I am facing is that my script is unable to detect alerts. Scenario: I open the application, pass my credentials and press Confirm. On Confirm, the application opens with an Alert. Screenshot of the Alert Shown below: I am using Java, Selenium WebDriver, ChromeDriver, and testng. i am using the codes shows below : uk.setLogin("", ""); uk.getLogin(); WebDriverWait wait = new WebDriverWait(Driver, 10); wait.until

Unable to detect Alert using ChromeDriver?

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How to make Java application use all CPU groups

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问题 I am running a java application on Intel(R) Xeon(R) machine which has 72 CPUs (with Hyperthreading on). Since, Microsoft groups CPUs into two groups if there are more than 64 CPUs, the java application uses only 1 group (or in other words 36 CPUs). See the snapshots below for the grouping and CPU usage details. As we can see, the java application is using 36 CPUs at capacity but not able to use other CPUs. I added +UseNUMA in JVM parameters but it did not work. Does anyone know of JVM option

How to use a JPanel as JButton?

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问题 I must use a swing-ui designer tool to create my UI, that only supports graphically editing JPanels. Those panels (they basically contain complex button designs) to work like a JButton. I cannot use anything other than JPanel as base class of these panels (UI editor limitation). What is the most generic solution to do this? Create a custom button that uses the panel's draw method instead of it's own? Create a base-panel class that reimplements the whole button? Another more elegant solution?

Stopping a thread in java CompletableFuture after timeout

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问题 I have an async chain in my java code that i want to stop after a certain timeout so i created a threadPool with some threads and called the CompletableFuture like this ExecutorService pool = Executors.newFixedThreadPool(10); than i have a cyclic method that loads data from the db and executes some task on it, once all the CompletableFutures are completed its doing it again CompletableFuture<MyObject> futureTask = CompletableFuture.supplyAsync(() -> candidate, pool) .thenApply(Task1::doWork)

栈------表达式求值

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栈的应用---表达式求值 1.简单计算器 Problem Description 读入一个只包含 +, -, *, / 的非负整数计算表达式，计算该表达式的值。 Input 测试输入包含若干测试用例，每个测试用例占一行，每行不超过200个字符，整数和运算符之间用一个空格分隔。没有非法表达式。当一行中只有0时输入结束，相应的结果不要输出。 Output 对每个测试用例输出1行，即该表达式的值，精确到小数点后2位。 Sample Input 1 + 2 4 + 2 * 5 - 7 / 11 0 Sample Output 3.00 13.36 Source 浙大计算机研究生复试上机考试-2006年 #include <iostream> #include <stack> #include < string > #include <cstdio> using namespace std; stack < double > opnd; // 运算对象栈 stack< char > optr; // 运算符号栈 void f() // 取栈顶元素运算 { double tmp; char key= optr.top(); optr.pop(); double x= opnd.top(); opnd.pop(); double y= opnd.top(); opnd.pop(); switch

What is the use of static fields PI_ENABLE_OUTPUT_ESCAPING & PI_DISABLE_OUTPUT_ESCAPING and how can we use them?

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问题 I am new to jaxp and has no idea of using the above static fields and what they mean ? Need its explanation along with examples. Thanks in advance 回答1: XSLT has a feature called "disable output escaping" that tells the serializer to output <a> as <a> whereas it would normally output <a> . This is a hack that is best avoided, for many reasons, one of which is that it requires a special side-channel for the transformation engine to communicate with the serializer (so the transformer can tell

Not able to upload large files

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问题 I would like to upload large amount of image file (max size 10mb) for that I am using following configuration is struts.xml <interceptors> <interceptor-stack name="fileUploadStack"> <interceptor-ref name="exception" /> <interceptor-ref name="alias" /> <interceptor-ref name="servletConfig" /> <interceptor-ref name="prepare" /> <interceptor-ref name="i18n" /> <interceptor-ref name="chain" /> <interceptor-ref name="debugging" /> <interceptor-ref name="profiling" /> <interceptor-ref name=

EventBus comunication between activity and service

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问题 I'm working on an Android application with EventBus library. I have an activity and a service. I want to to fire an event from activity and receive it on service. The activity is: public class MainActivity extends AppCompatActivity { public static final String TAG="ACTIVITY"; @Subscribe(threadMode = ThreadMode.MAIN) public void onMessageEvent(StartEvent event) { Log.d(TAG, "Received message"); Snackbar.make(fab, "Stop task", Snackbar.LENGTH_LONG).show(); txtMessage.setText(event.message); };