sun.misc.Unsafe in code generation

[denis-fokin]

Description

Our tests may contain usages of sun.misc.Unsafe class. Removal of sun.misc.Unsafe class is a backward incompatible change in Java internal API. Tests that have been generated this way cannot be run with Java 9+.

Expected behavior

The generated code does not contain sun.misc.Unsafe invocations.

Environment

Run the utbot-framework tests, find generated tests with unsafe.

Potential alternatives

For Java 9 it was possible to use flags in order to allow internal API usage. But it does not work for higher versions of Java.

Context

No additional context.

[dtim]

I think there are two unrelated topics.

1. The engine sometimes generates calls to Unsafe that should not be present (see Module-private JDK packages are used in generated tests #884 for an example and further details). I suppose that we would mostly get jdk.internal.misc.Unsafe for incorrectly processed JDK calls, although sun.misc.Unsafe can be produced during analysis of user code and third-party libraries.

2. References to sun.misc.Unsafe can be correctly generated when UnitTestBot analyses the code that refers to sun.misc.Unsafe in its public API (e.g., as a class field, a method parameter, or a return value). In this case, I suppose that the usage of sun.misc.Unsafe is legit and relatively safe. As far as I understand, sun.misc.Unsafe is considered a critical API by JEP 260 and should be present in current (and probably future) JDK releases (see this article for an overview).