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Integrating Apache Spark into your existing Hadoop system – Part I

June 22, 2016

As evidenced by our previous blog post, Statistics is Eating the World, data is at the very center of Wealthfront’s values. At Wealthfront, fields ranging from research, analytics to marketing, client services, human resources and even employee productivity all heavily rely on data in their decision makings. Such a variety of data sources and requirements need… 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

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

How We Avoid A/B Testing Errors with Shrinkage

October 29, 2015

At Wealthfront, we use A/B tests to make our services more effective, informative, and convenient. Each A/B test consists of two or more variants of a feature or design, which we expose to visitors at random until we have have enough data to infer which is better. In a previous post, we explained why we… Read more

Testing JavaScript Modules

October 13, 2015

In our previous post we outlined benefits of writing JavaScript in modules. One benefit we didn’t mention was how much more testable JavaScript modules are. In your test file you can require the module under test and let the require system import any dependencies. The goal of this post is to outline some of the… Read more

Advice for the Transition from College to Industry

September 29, 2015

The transition from college to industry came with quite a few surprises and lessons. Reflecting back on own my experience, I want to share a few insights I’ve gained. Additionally I want to share habits I formed during my undergraduate that transitioned well, as well as those that required significant changes in order to assimilate… Read more