Internship: Java Team: Lambda Inlining @ Guardsquare in Leuven (BE)


016 92 06 46

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Duration: 1+ months



In our Leuven-based Java team we work on manipulating Java bytecode. All our software is based on our open source bytecode manipulation library ProGuardCORE ( ).
On top of ProguardCORE we mainly develop 2 different products: ProGuard and DexGuard. ProGuard is a shrinker and optimizer for all Java and Android applications, it makes them smaller and faster. DexGuard is a code hardening tool, which makes Android apps harder to understand for a reverse engineer.



Nowadays more and more applications use a lot of lambda functions. Our current optimiser does not currently handle those and could use some improvements on that front. A lambda inlining functionality would optimize code like this:

void foo(lambda){
  print(‘start operation”)
  print(‘end operation”)

foo(a -> {some code using a})

into this:

  print(‘start operation”)
  some code using a
  print(‘end operation”)

This eliminates the whole lambda creation and the process of passing it as parameter while calling f() and speeds up code execution. 
In this internship you will get acquainted with automated java bytecode manipulation. You will create a new pass which detects places where lambdas can be inlined, perform the inlining, and make sure that such modifications can be applied on real-world applications. 



  • Java/Kotlin experience
  • Interest in Java bytecode/JVM-level


About Guardsquare:

Guardsquare offers the most complete approach to mobile application security on the market. Built on the open source ProGuard technology, Guardsquare’s software integrates seamlessly across the development cycle. From app security testing to code hardening to real-time visibility into the threat landscape, Guardsquare solutions provide enhanced mobile application security from early in the development process through publication.

More than 900 customers worldwide across all major industries rely on Guardsquare to help them identify security risks and protect their mobile applications against reverse engineering and tampering.

Guardsquare is based in Leuven (Belgium) with offices in Boston (USA) and Munich (Germany).



At Guardsquare, we take pride in being a diverse and multicultural company with team members representing numerous nationalities. We value different perspectives and opinions throughout the business which has contributed to our being the market leader in mobile application security. 

You will be part of a dynamic team that strives for excellence and focuses on continuous education and enhancement in skills. We encourage & empower our trusted colleagues to share their opinions, actively collaborate, and continue to learn and grow.