java-questdb-client fails to build on JDK 26: FDBigInteger no longer accessible in jdk.internal.math

[Knurav]

To reproduce

Environment

• OS: Ubuntu 25.10 (Questing Quokka), x86_64
• Kernel: 6.17.0-41-generic
• JDK: 26 (fails) | JDK 25 succeeds as a workaround
• Maven: 3.9.11 (IntelliJ IDEA embedded distribution)
• Commit: 0b9b576

Steps to reproduce

1. Clone questdb and initialize the java-questdb-client submodule at commit 0b9b576
2. Build under JDK 26: mvn clean package -DskipTests
3. Compilation fails in the questdb-client module

Expected behavior
questdb-client builds successfully under JDK 26, as it does under JDK 25.

Actual behavior
Compilation fails with three errors, all pointing to FDBigInteger no longer being accessible from jdk.internal.math:

[ERROR] core/src/main/java11/io/questdb/client/std/FdBig.java:[27,24] error: FDBigInteger is not public in jdk.internal.math; cannot be accessed from outside package
[ERROR] core/src/main/java11/io/questdb/client/std/FdBig.java:[45,18] error: FDBigInteger is not public in jdk.internal.math; cannot be accessed from outside package
[ERROR] core/src/main/java11/io/questdb/client/std/FdBig.java:[47,18] error: FDBigInteger is not public in jdk.internal.math; cannot be accessed from outside package

QuestDB version:

1.3.10-SNAPSHOT (commit 0b9b576)

OS, in case of Docker specify Docker and the Host OS:

Ubuntu 25.10 (Questing Quokka), x86_64, kernel 6.17.0-41-generic - not using Docker

File System, in case of Docker specify Host File System:

ext4

Full Name:

Varun Sanalkumar

Affiliation:

Independent contributor

Have you followed Linux, MacOs kernel configuration steps to increase Maximum open files and Maximum virtual memory areas limit?

• Yes, I have

Additional context

Cause:
In JDK 26, FDBigInteger is no longer declared public

[Knurav]

The visibility change comes from openjdk/jdk@deb7edb (JDK-8366017, Nov 2025)