Use the latest version of Scala

Oct 13, 2025 by wbrum.org 49 views

Scala 3.6.4 is Supposed to be JDK24 Compatible, But Isn't

Scala 3.6.4 is the latest version of the Scala programming language, which is designed to be compatible with Java 24. However, as we will discuss in this article, Scala 3.6.4 is not entirely compatible with JDK 24, as evidenced by the warnings displayed when running the Scala interpreter.

JDK compatibility refers to the ability of a programming language to run on top of a Java Development Kit (JDK). In other words, a language is JDK compatible if it can run on a JDK without any issues or warnings. Scala 3.6.4 is designed to be compatible with JDK 24, which means that it should be able to run on a JDK 24 without any issues.

When running the Scala interpreter, we get the following warnings:

WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
WARNING: sun.misc.Unsafe::objectFieldOffset has been called by scala.runtime.LazyVals$ (file:/data/opt/periscope-tools-1.1.0/scala3-3.6.4/maven2/org/scala-lang/scala3-library_3/3.6.4/scala3-library_3-3.6.4.jar)
WARNING: Please consider reporting this to the maintainers of class scala.runtime.LazyVals$
WARNING: sun.misc.Unsafe::objectFieldOffset will be removed in a future release
WARNING: A restricted method in java.lang.System has been called
WARNING: java.lang.System::load has been called by org.jline.nativ.JLineNativeLoader in an unnamed module (file:/data/opt/periscope-tools-1.1.0/scala3-3.6.4/maven2/org/jline/jline-native/3.27.1/jline-native-3.27.1.jar)
WARNING: Use --enable-native-access=ALL-UNNAMED to avoid a warning for callers in this module
WARNING: Restricted methods will be blocked in a future release unless native access is enabled

These warnings indicate that Scala 3.6.4 is using methods that are deprecated or restricted in JDK 24. Specifically, the warnings indicate that Scala 3.6.4 is using the sun.misc.Unsafe class, which is deprecated, and the java.lang.System class, which has restricted methods.

The fact that Scala 3.6.4 is not entirely compatible with JDK 24 means that it may not work correctly on a JDK 24. This could lead to issues such as:

Warnings and errors: As we have seen, Scala 3.6.4 displays warnings when running on a JDK 24. These warnings may indicate potential issues with the code.
Inconsistent behavior: The use of deprecated or restricted methods in JDK 24 may lead to inconsistent behavior in Scala 3.6.4.
Security issues: The use of restricted methods in JDK 24 may lead to security issues in Scala 3.6.4.

In conclusion, while Scala 3.6.4 is designed to be compatible with JDK 24, it is not entirely compatible. The warnings displayed when running the Scala interpreter indicate that Scala 3.6.4 is using deprecated or restricted methods in JDK 24. This may lead to issues such as warnings and errors, inconsistent behavior, and security issues. Therefore, it is essential to be aware of these issues and take necessary steps to address them.

To address the issues with Scala 3.6.4 and JDK 24, we recommend the following:

Use the latest version of Scala: The latest version of Scala may have fixed the issues with JDK 24 compatibility.
Use the latest version of JDK: The latest version of JDK may have fixed the issues with deprecated or restricted methods.
Use the --enable-native-access=ALL-UNNAMED flag: This flag can be used to avoid warnings for callers in unnamed modules.
Report issues to the maintainers: If you encounter issues with Scala 3.6.4 and JDK 24, report them to the maintainers of the Scala language.

To improve the compatibility of Scala 3.6.4 with JDK 24, we recommend the following:

Fix deprecated and restricted methods: The maintainers of the Scala language should fix the deprecated and restricted methods used in Scala 3.6.4.
Improve testing: The maintainers of the Scala language should improve testing to ensure that Scala 3.6.4 is compatible with JDK 24.
Provide better error messages: The maintainers of the Scala language should provide better error messages to help users diagnose issues with Scala 3.6.4 and JDK 24.

A: The issue is that Scala 3.6.4 is not entirely compatible with JDK 24, as evidenced by the warnings displayed when running the Scala interpreter. These warnings indicate that Scala 3.6.4 is using deprecated or restricted methods in JDK 24.

A: The warnings displayed when running the Scala interpreter are:

WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
WARNING: sun.misc.Unsafe::objectFieldOffset has been called by scala.runtime.LazyVals$ (file:/data/opt/periscope-tools-1.1.0/scala3-3.6.4/maven2/org/scala-lang/scala3-library_3/3.6.4/scala3-library_3-3.6.4.jar)
WARNING: Please consider reporting this to the maintainers of class scala.runtime.LazyVals$
WARNING: sun.misc.Unsafe::objectFieldOffset will be removed in a future release
WARNING: A restricted method in java.lang.System has been called
WARNING: java.lang.System::load has been called by org.jline.nativ.JLineNativeLoader in an unnamed module (file:/data/opt/periscope-tools-1.1.0/scala3-3.6.4/maven2/org/jline/jline-native/3.27.1/jline-native-3.27.1.jar)
WARNING: Use --enable-native-access=ALL-UNNAMED to avoid a warning for callers in this module
WARNING: Restricted methods will be blocked in a future release unless native access is enabled

A: These warnings indicate that Scala 3.6.4 is using methods that are deprecated or restricted in JDK 24. Specifically, the warnings indicate that Scala 3.6.4 is using the sun.misc.Unsafe class, which is deprecated, and the java.lang.System class, which has restricted methods.

A: The potential issues with Scala 3.6.4 and JDK 24 compatibility are:

Warnings and errors: As we have seen, Scala 3.6.4 displays warnings when running on a JDK 24. These warnings may indicate potential issues with the code.
Inconsistent behavior: The use of deprecated or restricted methods in JDK 24 may lead to inconsistent behavior in Scala 3.6.4.
Security issues: The use of restricted methods in JDK 24 may lead to security issues in Scala 3.6.4.

A: To address the issues with Scala 3.6.4 and JDK 24 compatibility, you can:

Use the latest version of Scala: The latest version of Scala may have fixed the issues with JDK 24 compatibility.
Use the latest version of JDK: The latest version of JDK may have fixed the issues with deprecated or restricted methods.
Use the --enable-native-access=ALL-UNNAMED flag: This flag can be used to avoid warnings for callers in unnamed modules.
Report issues to the maintainers: If you encounter issues with Scala 3.6.4 and JDK 24, report them to the maintainers of the Scala language.

A: To improve the compatibility of Scala 3.6.4 with JDK 24, the maintainers of the Scala language should:

Fix deprecated and restricted methods: The maintainers of the Scala language should fix the deprecated and restricted methods used in Scala 3.6.4.
Improve testing: The maintainers of the Scala language should improve testing to ensure that Scala 3.6.4 is compatible with JDK 24.
Provide better error messages: The maintainers of the Scala language should provide better error messages to help users diagnose issues with Scala 3.6.4 and JDK 24.

A: It is not recommended to use Scala 3.6.4 with JDK 24 for production use due to the compatibility issues. It is recommended to use the latest version of Scala and JDK to ensure compatibility and avoid potential issues.