Menu

Reflective Metatesting. Protecting You from Yourself and Everybody Else.

November 16, 2016

Infrastructure projects often take user-defined configuration classes as input. I’ve worked on several during my tenure at Wealthfront. You cannot trust the validity of these configurations, even if you wrote them yourself. A pattern I’ve grown to love is writing JUnit tests that use reflection to gather all the input classes to run a suite… Read more

Enforce REST API Standard with Swagger

August 31, 2016

At Wealthfront, we have an API server which exposes a REST API that’s consumed by our iOS and Android apps. Recently we decided to migrate our web frontend to use the REST API because we believe it would be beneficial to have all of our frontends sharing a single data source. We identified a few… Read more

Connecting to an FTPS Server with SSL Session Reuse in Java 7 and 8

June 10, 2016

“Good programmers write good code… Great programmers reuse great code.”  Or so I told myself as I snagged an Apache Commons class to connect to a new vendor’s FTPS server.  Several hours of debugging later, however, I realized to my dismay that the omnipotent Apache Commons did not support a major security feature required by most modern FTPS servers.  This post outlines my process… Read more

How to Make Your Persistent Queues Run Faster Safely

May 04, 2016

What is a Persistent Queue? A persistent queue is a list of objects that persist in the database waiting to be polled and processed in some way. Usually it is a table that has columns for data, timestamp of when the object persisted, and timestamp of when the object is polled. As opposed to an… Read more

Identifying Non-Heap Class Leaks

April 18, 2016

At Wealthfront, a significant portion of our backend applications are written in Java. The Java Virtual Machine (JVM) uses Garbage Collection (GC) for memory management, this forces us to pay close attention to its characteristics and behavior. Every JVM service we run accumulates JVM and application-level statistics, spools these metrics into a statsd server, and… Read more

Pattern matching in Java with the Visitor pattern

February 11, 2015

I once read an essay—I cannot find it now—that talked about how learning a more advanced programming language can improve your coding even in a language that lacks those features because those language features are really ways of thinking, and there’s no reason you cannot think in terms of more powerful abstractions just because you… Read more