Exceptions thrown in a task submitted to a thread pool will just disappear. You won’t even see the log. You can catch java.lang.Exception and handle it. But to make things even better, please catch java.lang.Throwable instead. In theory, it’s not recommended to catch a Throwable. But to be pragmatic, it’s important for you to see …
Please catch Throwable in a task submitted to a thread pool Read More »
There are a few strange things about Condition related code in Java concurrency. I’ll use the following code to show you. The code is about one cup and two threads. One thread is trying to fill it, the other to drink from it. The code uses explicit Lock + Condition API. But what I’m going …
Condition variable related code is hard to understand. So let me explain Read More »
If an exception is thrown from some thread and it’s not caught, it will be printed in the console. In your server, if the console output doesn’t go to any file or any log cloud, it will just disappear and you won’t understand what error has happened. Example 1: your multi-thread batch job seems to …
Make sure Java App’s console is collected somewhere Read More »
subscribe() is normally used to register a listener, but in Project Reactor it is used for both registering a listener and trigger a flow. onNext , onComplete are normally used for listeners to handle next and complete signals, but Project Reactor uses them as the names of the events – so there are onNext signals …
Take a look at the following union sql fragment. What if includeFoo is false? You will end up with union all (select * from bar) , which is not legal sql. There must be a result set before “union all” The solution is to use <trim/> tag It means: if what’s inside <trim/> starts with …
And the unit test:
Requirements Some of the sub-projects need to run flyway as a gradle task We want a single command line to do the flyway migrations for all the sub-projects mentioned above Solution Apply flyway plugin in these sub-projects Config flyway in these sub-projects Create a root-project task to call the flyway tasks in the sub-projects Code …
In intellij, create such a live template:
Install chromedriver You want to make the following line of code run successfully. In windows, you need to download chrome driver from https://chromedriver.chromium.org/downloads and put it in system’s path (An alternative is to set the executable file’s path as a system property “webdriver.chrome.driver”, not beautiful) In *nix or linux-based Docker, you can Options needed for …