assistant: Java's native image mode is provided by the GraalVM Native Image tool, which compiles Java applications into platform-specific executables. While this tool offers several benefits such as faster startup times and reduced memory usage, it does not support all features available in the standard Java runtime environment.

Here's a list of examples of features that aren't supported or have limited support in Java's native image mode:

1. Reflection: Native Image has limited support for reflection, and you need to explicitly specify which classes, methods, and fields you want to make available for reflection at build time using a JSON configuration file.

2. Dynamic class loading: Loading classes at runtime using Class.forName() or custom class loaders is not supported, as native images have a closed world assumption where all classes and their dependencies must be known during compilation.

3. Java Native Interface (JNI): There is limited support for JNI, and you need to provide a specific configuration for native methods and libraries during the native image generation process.

4. Finalizers: Native Image does not support finalizers, so you need to find alternatives like using the try-with-resources statement or implementing the AutoCloseable interface.

5. Weak references, soft references, and phantom references: These types of references are not fully supported, and their behavior may differ from the standard JVM.

6. Some JDK APIs: Some JDK APIs, like sun.misc.Unsafe, are not supported or have limited functionality. It's recommended to use alternative APIs or solutions.

7. Just-In-Time (JIT) compilation: Since native images are ahead-of-time (AOT) compiled, there is no JIT compilation at runtime, which may impact the performance of some applications that benefit from runtime optimizations.

8. Java Management Extensions (JMX): Native Image does not support JMX, so you will need to find alternative ways to monitor and manage your application.

9. SecurityManager: Native Image does not support the SecurityManager, and you need to rely on other security measures like proper input validation, secure coding practices, and operating system-level security features.

10. Some garbage collectors: Native Image supports a subset of the garbage collectors available in the JVM, such as the Serial GC and G1 GC. You might need to adjust your application to work with the supported garbage collectors.



Keep in mind that GraalVM Native Image is an evolving technology, and some of these limitations may be addressed in future releases. It is essential to consult the official documentation for the latest information on unsupported features and workarounds.

assistant: Sure, here are some examples of Java features that may not be supported in native image mode:

1. Dynamic Class Loading: Native image mode requires all classes to be present at compile time. Therefore, any code that relies on dynamic class loading at runtime may not work properly in native image mode.
2. Reflection: Reflection is a powerful feature in Java that allows the runtime behavior of an application to be inspected and modified. However, it can also be used in ways that are difficult to optimize for ahead-of-time compilation. Therefore, some uses of reflection may not be supported in native image mode.
3. Dynamic proxies: Dynamic proxies are a feature of the Java language that allow for the creation of objects that implement interfaces at runtime. However, this feature relies on dynamic class loading and may not work properly in native image mode.
4. Thread interruption: Native image mode does not support thread interruption in the same way that the Java virtual machine does. Therefore, code that relies heavily on thread interruption may not work properly in native image mode.
5. Some third-party libraries: Some third-party libraries may not work properly in native image mode, either because they use features that are not supported or because they rely on dynamic class loading or other runtime behavior that is not compatible with native image mode.

It is important to note that these are just a few examples of features that may not be supported in native image mode, and that the specific limitations may vary depending on the version of GraalVM and the configuration of your application. Therefore, it is recommended to consult the GraalVM documentation and perform thorough testing when compiling applications to native code.