Native mode

Things to consider before you run your application in native mode.

Character encodings

By default only the following Charsets are available in native mode (source):

Charset.defaultCharset(), US-ASCII, ISO-8859-1, UTF-8, UTF-16BE, UTF-16LE, UTF-16

If you expect your application to need any encoding not included in this set or if you see an UnsupportedCharsetException thrown in the native mode, please add the following entry to your application.properties:

quarkus.native.add-all-charsets = true

See also quarkus.native.add-all-charsets in Quarkus documentation.

Locale

By default, only the building JVM default locale is included in the native image. Quarkus provides a way to set the locale via application.properties, so that you do not need to rely on LANG and LC_* environement variables:

quarkus.native.user-country=US
quarkus.native.user-language=en

There is also support for embedding multiple locales into the native image and for selecting the default locale via GraalVM command line options -H:IncludeLocales=fr,en, H:+IncludeAllLocales and -H:DefaultLocale=de. You can set those via the Quarkus quarkus.native.additional-build-args property.

Embedding resources in the native executable

Resources accessed via Class.getResource(), Class.getResourceAsStream(), ClassLoader.getResource(), ClassLoader.getResourceAsStream(), etc. at runtime need to be explicitly listed for including in the native executable.

This can be done using Quarkus quarkus.native.resources.includes and quarkus.native.resources.excludes properties in application.properties file as demonstrated below:

quarkus.native.resources.includes = docs/*,images/*
quarkus.native.resources.excludes = docs/ignored.adoc,images/ignored.png

In the example above, resources named docs/included.adoc and images/included.png would be embedded in the native executable while docs/ignored.adoc and images/ignored.png would not.

resources.includes and resources.excludes are both lists of comma separated Ant-path style glob patterns. Please refer to Quarkus documentation for more details.

Using the onException clause in native mode

When using Camel onException handling in native mode, it is the application developers responsibility to register the exception classes for reflection.

For instance, with an exception handler like this

onException(MyException.class).handled(true);
from("direct:route-that-could-produce-my-exception").throw(MyException.class);

the class MyException should be registered for reflection, see more in Registering classes for reflection.

Registering classes for reflection

By default, dynamic reflection is not available in native mode. Classes for which reflective access is needed, have to be registered for reflection at compile time.

In many cases, application developers do not need to care because Quarkus extensions are able to detect the classes that require reflection and register them automatically.

However, in some situations, Quarkus extensions may miss some classes and it is up to the application developer to register them. There are two ways to do that:

  1. The @io.quarkus.runtime.annotations.RegisterForReflection annotation can be used to register classes on which it is used, or it can also register third party classes via its targets attribute.

    import io.quarkus.runtime.annotations.RegisterForReflection;
    
    @RegisterForReflection
    class MyClassAccessedReflectively {
    }
    
    @RegisterForReflection(
        targets = {
            org.third-party.Class1.class,
            org.third-party.Class2.class
        }
    )
    class ReflectionRegistrations {
    }
  2. The quarkus.camel.native.reflection options in application.properties:

    quarkus.camel.native.reflection.include-patterns = org.apache.commons.lang3.tuple.*
    quarkus.camel.native.reflection.exclude-patterns = org.apache.commons.lang3.tuple.*Triple

    For these options to work properly, the artifacts containing the selected classes must either contain a Jandex index (META-INF/jandex.idx) or they must be registered for indexing using the quarkus.index-dependency.* options in application.properties - e.g.

    quarkus.index-dependency.commons-lang3.group-id = org.apache.commons
    quarkus.index-dependency.commons-lang3.artifact-id = commons-lang3

Registering classes for serialization

If serialization support is requested via quarkus.camel.native.reflection.serialization-enabled, the classes listed in CamelSerializationProcessor.BASE_SERIALIZATION_CLASSES are automatically registered for serialization.

Users can register more classes using @io.quarkus.runtime.annotations.RegisterForReflection(serialization = true).