Eclipse recently has suffered increasing numbers of questionable autocompletions — sometimes auto-wrongly replacing perfectly good code typed by the developer.
While there might be a few underlying issues, I found replacing “map.put()” with “map.compute()” particularly annoying and went to investigate. Here’s the solution.
Just today, I found the “amusing” fact that Tomcat server developers have taken it upon themselves to delete support for the HTTP Status Reason.
Think “200 OK” or “404 Not Found”. Even for applications sending a reason & clients expecting it, Tomcat is coded to explicitly drop the value — sending just a bald 200 or 404.
Unsurprisingly for those with the slightest knowledge of protocol compatibility, this is now breaking clients in the wild.
When processing SQL data in Spark, sometimes single rows are not the right unit — your calculation may need a collection or group of records as input.
This post shows how to group SQL data for use in Spark. Continue reading
Today I got a very unusual error while trying to debug the DeepLearning4J framework.
Conditional breakpoint encountered runtime exception. Reason: java.lang.InternalError: Got MethodID of ReferenceType that is not a member of the ReferenceType occured retrieving stack frames.
Continuing last month’s theme of searching Git history — here we look at how to find the source of changes, even after other people have worked on (or reformatted) the area in question.
The question: which commit actually introduced a given string into the file? Continue reading
Great post on inheritance from the Sicpers blog, and why — as a concept — it often fails in OO languages such as Java.
This blog post can help you understand why:
- “Cat and Dog extend Animal” is poor use of OO.
- “Square extends Rectangle” is poor use of OO.
From my own experience, I’ve moved to primarily using inheritance in only two ways: Continue reading
Working on many separate enhancements.. How to find which branch my changes to a particular file are on? And if a file was deleted, how can I find that?
Luckily, Git can help us! Continue reading
Last week I had to debug some unstable tests, which were only launched externally from Ant (launched from Maven). The tests were largely not directly runnable from the IDE, and did not run equivalently.
Obviously this is outdated practice and not good TDD, but sometimes we need to work with such assets anyway 🙂
Given that, how could I debug & fix these tests? Continue reading
When investigating complex issues with Maven or command-line tools, it is often helpful to capture the output to a file for further analysis.
This tip shows how to capture both ‘stdout’ and ‘stderr’ to capture a complete authoritative output. Continue reading
This is a confirmed JDK bug. Just three lines of code to crash the Windows JVM.