Lucene/Solr tests have a special rule that records memory usage in static fields before and after test, so we can detect memory leaks. This check dives into JDK classes (like java.lang.String to detect their size). As Java 9 build 148 completely forbids setAccessible on any runtime class, we have to change or disable this check:
- As first step I will only add the rule to LTC, if we not have Java 8
- As a second step we might investigate how to improve this
Robert Muir had some ideas for the 2nd point:
- Don't dive into classes from JDK modules and instead "estimate" the size for some special cases (like Strings)
- Disallow any static field in tests that is not final (constant) and points to an Object except: Strings and native (wrapper) types.
In addition we also have RAMUsageTester, that has similar problems and is used to compare estimations of Lucene's calculations of Codec/IndexWriter/IndexReader memory usage with reality. We should simply disable those tests.