[LUCENE-7595] RAMUsageTester in test-framework and static field checker no longer works with Java 9

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 6.4, 7.0
• Component/s: general/test
• Labels: Java9
• Lucene Fields: New
• Assignee: Uwe Schindler
• Reporter: Uwe Schindler
• Created: 16/Dec/16 08:27
• Updated: 28/Aug/22 15:07
• Resolved: 29/Dec/16 01:13

Description

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

rcmuir 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.

Issue Links

• is related to: LUCENE-7604 TestLRUQueryCache.testDetectMutatedQueries does not work on Java 9 b150
• is related to: LUCENE-6989 Implement MMapDirectory unmapping for coming Java 9 changes
• relates to: LUCENE-8642 RamUsageTester.sizeOf ignores arrays and collections if --illegal-access=deny