Compilation failure on branch-4.17: ConcurrentLongHashMap uses Java `record` but the branch targets Java 8

[eolivelli]

Description

Branch branch-4.17 fails to compile after commit 0e1bddd ([Fix] ConcurrentLongHashMap throw ArrayIndexOutOfBoundsException, #4771) was backported to it.

The commit introduces a Java record declaration in ConcurrentLongHashMap:

private record Table<V>(long[] keys, V[] values, int capacity) { }

The record keyword requires Java 16+, but on branch-4.17 the root pom.xml sets:

<maven.compiler.source>8</maven.compiler.source>
<maven.compiler.target>8</maven.compiler.target>

so the file fails to parse.

Build error

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.12.1:compile (default-compile) on project bookkeeper-server: Compilation failure: Compilation failure:
[ERROR] .../ConcurrentLongHashMap.java:[320,29] ';' expected
[ERROR] .../ConcurrentLongHashMap.java:[320,32] illegal start of type

Affected branches

• branch-4.17 — broken (Java 8 target).
• master — not affected (Java 17 target).

Proposed fix

Replace the record with an equivalent static final nested class exposing keys(), values() and capacity() accessors, preserving the existing call sites.