When the paper “Practical Pluggable Types for Java” was written, it was Static Typing Winter. Programmers flocked to dynamically-typed languages such as JavaScript and Python, whose flexibility enabled rapid production of applications. Programmers rejected type systems as too hard to understand, suffering too many false positives, and not applicable to the most important problems. Programmers were not moved by the claims and exhortations of programming language theoreticians; they experienced the costs as greater than the benefits.

Today, the tide has begun to turn, thanks to the contributions of many researchers. The costs have been reduced by creating rich, expressive type systems whose implementations are precise, yet which are simple, easy to understand, and focused on real-world problems. The benefits have been increased by expanding the scope of problems investigated, and by programmers’ recognition of the cost of errors and security vulnerabilities, which cannot be detected through testing alone.

This talk is in two parts. The first part surveys the antecedents, technical accomplishments, and remaining challenges for researchers who wish to create practical type systems that solve real-world problems. The second part is a personal reflection on the motivations for the work and the reasons that it had impact, which go beyond the 2008 paper.

Michael D. Ernst is a Professor in the Computer Science & Engineering department at the University of Washington.

Ernst’s research aims to make software more reliable, more secure, and easier (and more fun!) to produce. His primary technical interests are in software engineering, programming languages, type theory, security, program analysis, bug prediction, testing, and verification. Ernst’s research combines strong theoretical foundations with realistic experimentation, with an eye to changing the way that software developers work.

Ernst is an ACM Fellow (2014) and received the inaugural John Backus Award (2009) and the NSF CAREER Award (2002). His research has received an ACM SIGSOFT Impact Paper Award (2013), 8 ACM Distinguished Paper Awards (FSE 2014, ISSTA 2014, ESEC/FSE 2011, ISSTA 2009, ESEC/FSE 2007, ICSE 2007, ICSE 2004, ESEC/FSE 2003), an ECOOP 2011 Best Paper Award, honorable mention in the 2000 ACM doctoral dissertation competition, and other honors. In 2013, Microsoft Academic Search ranked Ernst #2 in the world, in software engineering research contributions over the past 10 years.

Dr. Ernst was previously a tenured professor at MIT, and before that a researcher at Microsoft Research.