Jakery

Gradle-powered toolbox for "pre locating" groups of Java code elements at compile time, meant to replace many of the use cases of the now-abandoned Reflections library.

Descriptors resolved by Jakery are stored in a compact form within META-INF/.jakery via jakery-agent, then lazily read back and resolved by jakery-runtime. Correct usage of this system may be much faster and more reliable than the classical approach.

Important

Jakery's tooling requires a Java 25 build environment (Gradle 9.1.0+) due to its use of the Class-File API, however all runtime components target Java 8. Using Jakery will not prevent you from targeting older JREs.

Getting Started

Adding the Gradle plugin will automatically create the jakery source set to hold your JakeryAgent implementation and related code. This code will be responsible for declaring the groups used at runtime.

Kotlin DSL

plugins {
    id("java")
    id("io.github.wasabithumb.jakery-gradle") version "0.1.0"
}

repositories {
    mavenCentral()
}

Groovy DSL

plugins {
    id 'java'
    id 'io.github.wasabithumb.jakery-gradle' version '0.1.0'
}

repositories {
    mavenCentral()
}

Note

By default, this plugin configures the main source set to depend on io.github.wasabithumb:jakery-runtime and the jakery source set to depend on io.github.wasabithumb:jakery-agent. If a repository such as mavenCentral() which holds these artifacts is not declared, these dependencies will fail to resolve.

Example

Take an interface zoo.Animal and several classes within zoo.impl which implement this interface. Here's how you might use Jakery to list all of these implementation classes at runtime:

src/jakery/java/zoo/ZooJakeryAgent.java

package zoo;

import io.github.wasabithumb.jakery.agent.JakeryAgent;
import io.github.wasabithumb.jakery.agent.set.ClassSet;
import java.lang.reflect.Modifier;

public final class ZooJakeryAgent extends JakeryAgent {
    
    @Group("animals")
    public ClassSet findAnimals() {
        return find("zoo.impl")
                .withSupertype(Animal.class)
                .withoutModifiers(Modifier.INTERFACE | Modifier.ABSTRACT);
    }
    
}

src/main/java/zoo/Animals.java

package zoo;

public final class Animals {
    
    static Set<Class<?>> implClasses() {
        return Jakery.jakery().typeGroup("animals");
    }
    
}

Tip

The jakery source set inherits the classpath of the main source set. You can leverage this to define a GroupNames class within main enumerating the names of groups defined by your agent that is visible for use in both the @Group annotation and the Jakery runtime group accessors.

Note

@Group methods may return ClassSet, FieldSet, MethodSet or ConstructorSet. These are accessed at runtime via typeGroup, fieldGroup, methodGroup and constructorGroup respectively. In the future, it may be possible to declare type groups containing primitive or array types.

Roadmap

• Support relocation via Shadow
• Negotiate behavior when multiple agent classes are present
• Improve documentation

License

Copyright 2026 Xavier Pedraza

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.