AWS diaries: serving HTML from lambda

AWS lambda is a neat feature that runs code in response to requests and transforms the code's output into some response. Requests can be an event occurring in the AWS platform such as an S3 modification or an HTTP request. The response is an MVC-style model which needs to pass through some network component, like … Continue reading AWS diaries: serving HTML from lambda →

The Model-View-Presenter-Controller pattern

In this post I'll talk about the MVPC (Model-View-Presenter-Controller) design pattern I use in client applications such as progressive web apps and mobile clients. It can be best understood as an evolution of the MVC (model-view-controller) pattern past the MVP (model-view-presenter) pattern. The basics: MVC and MVP You might want to skip this section if … Continue reading The Model-View-Presenter-Controller pattern →

Book of dark arts: storing data in the view

Pentagram, source Wikipedia. Towards the end of the year I'll indulge in the dark arts, join the goblins and leave my white architect hat under the Christmas tree where it belongs. I'm helping a friend (a technically minded, non-programmer) write his first mobile app . We wanted to keep everything simple: use technologies which can … Continue reading Book of dark arts: storing data in the view →

Thunderbird forgetting passwords

After a simultaneous Thunderbird upgrade and profile migration from Windows to Linux the mail program permanently forgets passwords. The setting: Thunderbird 52 on Windows Back up profile Restore profile to Thunderbird 60 on Linux Observe that all passwords to all accounts are lost even if entered again This seems to be some … Continue reading Thunderbird forgetting passwords →

Climbing the monolith

I love learning a term for a vague idea that has been with me for a while already; it gives the fuzzy cloud in my head a box to live in and a label to put under... not to mention convenient stowage when I need room for other things. One such illuminating moment was listening … Continue reading Climbing the monolith →

Phantomjs not showing text

TL;DR if Phantomjs doesn't show any text/fonts, give it a Truetype web font. Despite Phantomjs' [1] development slowing down [2] it still brings most of the features I need for regression testing web applications. And, thanks to Docker, it should be possible to operate it for a long time to come. Installing and operating Phantomjs … Continue reading Phantomjs not showing text →

Eclipse freezes on Windows 10 creator’s update

Symptoms: Eclipse used to work fine under Windows 10, suddenly hangs short after start. Solution: uninstall Linux subsystem or don't use Git in Eclipse Explanation: the Eclipse egit plugin looks for bash, which normally doesn't exist on Windows. When the Windows subsystem for Linux is installed, bash does exist, but blocks with a message ("click … Continue reading Eclipse freezes on Windows 10 creator’s update →

Getting test coverage reports for integration test

I'm a vociferous supporter of integration tests with an embedded servlet container and in this post I'll show how to get test coverage for the classes touched in those integration tests. All test coverage gauging tools I know instrument code under test either at build time or run time through Java agents. Because the code … Continue reading Getting test coverage reports for integration test →

Java synchronized method concurrent execution

I read this puzzle years ago (unfortunately I can't find the reference) but didn't appreciate it at the time. Java synchronized methods [1] can supposedly be invoked only by a single thread at a time. The essence of aforementioned puzzle was that, if the synchronized method obtains a lock on the object the method belongs … Continue reading Java synchronized method concurrent execution →

Debugging Spring REST bad request 400 codes

This happens way too often: you POST or PUT something to a Spring @RestController and Spring only tells you that there is a bad request, HTTP 400 code; no further explanations, no logs, no exceptions. Spring logs the error cause under the category "org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod" so you can enable logging for that in your log4j.properties: log4j.logger.org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod=DEBUG,stdout … Continue reading Debugging Spring REST bad request 400 codes →