Talk proposal: Java bytecode verification. When, how, or turn it off maybe?

[Nikita Lipsky]

Hi all,

The talk may be interesting considering deprecation of -Xverify:none in JDK
13 (https://bugs.java.com/bugdatabase/view_bug.do?bug_id=JDK-8214719) -
people should know why "-Xverify:none" is so dangerous.

Title: Java bytecode verification. When, how, or turn it off maybe?

Abstract: Today's  Java developers are increasingly relying on libraries
that generate Java bytecode at run time to effectively implement various
tricks that are hard or impossible to do in pure Java. However, while the
javac compiler is guaranteed to produce correct Java bytecode, shifting
down to the bytecode level requires that you keep track of its correctness
yourself. Otherwise, there is a chance to get a j.l.VerifyError at run time
upon the loading of a generated class, because the JVM passes all classes
through the Java bytecode verifier to enforce strict correctness
requirements. Therefore, knowing just the semantics of Java bytecode
instructions is often not enough to properly synthesize classes - you also
need to know how the Java bytecode verifier works, what bytecode it deems
correct, and what it does not. In this talk, we will learn what mission the
Java bytecode verifier carries out in the JVM, when and how it works,
whether it may affect the performance of your application, and why turning
it off is so dangerous.

Recording: ok

Bio:
Nikita works for Huawei on JVMs, compilers and new programming languages.
Before Huawei, Nikita had been the key figure in the Excelsior JET project
for over twenty years. Excelsior JET was a complete Java SE implementation
(JVM) with an AOT compiler, and Nikita took part in almost all activities
pertaining to that project, from core JVM development to product management
and support. In particular, he is the author of OSGi support at the JVM
level, the Java Runtime Slim-down technology - Java SE modularization
implemented in Excelsior JET since 2007, both Java bytecode verifiers,
Spring Boot support, and many other features.

Nikita
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