Objenesis Documentation

When client code requests an instantiator for a specific class, Objenesis can either create a new one or return a cached instance. Instantiators are thread-safe, so using cached instances is safe for concurrent usage.

Historically, Objenesis used a synchronized implementation for caching (Java 1.3 style), but modern versions use concurrent collections (Java 5+ style) to improve performance. Using a cache significantly reduces the time required to obtain an instantiator compared to creating one without a cache.

Objenesis provides different strategies for selecting how objects are instantiated. While performance differences between these strategies are generally minimal in practice, you can choose based on your requirements:

1. Standard Strategy: The default approach. It automatically deduces the best instantiator for your specific platform.
2. Single Strategy: Use this if you already know your platform and want to force the use of a single instantiator type that relies on reflection.
3. Custom Strategy: Use this if you want to avoid reflection entirely by providing a custom instantiator that always uses the new keyword.

To update the project versions across all modules, use the versions:set command with the all profile. After verifying the changes, you can either commit them or revert them.

# Set new version
mvn versions:set -DnewVersion=X.Y -Pall

# If successful, commit the changes
mvn versions:commit -Pall

# If something is wrong, revert the changes
mvn versions:revert -Pall

You can build the project using Maven with different profiles depending on the depth of the build required.

Basic Compilation

To perform a basic compilation of the application, run: mvn install

Full Build

To create source and javadoc JARs and run Spotbugs, use the full profile: mvn install -Pfull

# Basic build
mvn install

# Full build (includes javadoc, source jars, and spotbugs)
mvn install -Pfull

To run the project's benchmarks, package the project with the benchmark profile, navigate to the benchmark directory, and execute the launch script.

mvn package -Pbenchmark
cd benchmark
./launch.sh

Objenesis follows guidelines to ensure that builds are reproducible (the same source always produces the same binary result). Use these commands to verify compatibility and integrity:

• Check plugin compatibility: mvn artifact:check-buildplan -Pfull,all
• Build and install: mvn clean install -Pfull,all
• Compare the built artifact with the installed one: mvn clean verify artifact:compare -Pfull,all

# Check plugin compatibility
mvn artifact:check-buildplan -Pfull,all

# Build and install
mvn clean install -Pfull,all

# Compare artifact with installed one
mvn clean verify artifact:compare -Pfull,all

To run the Android TCK, you must first set up the Android environment.

Prerequisites

MacOs / *nix

1. Install the Android SDK: brew cask install android-sdk
2. Install platform-tools and build-tools via sdkmanager: sdkmanager "platform-tools" "build-tools"
3. Set the ANDROID_HOME environment variable: export ANDROID_HOME=$(realpath $(echo "$(dirname $(readlink $(which sdkmanager)))/../.."))

Windows

1. Install Android Studio.
2. Launch Android Studio and install the SDK and emulator.
3. Add the path used to install the SDK to your ANDROID_HOME environment variable.

Execution

1. Configure and launch a device (real or simulated). Note: Use API 26. Higher versions may require a signature that is not yet supported.
2. If using a real device, activate debug mode.
3. Run the build: mvn package -Pandroid

To deploy to the Sonatype Maven repository, add the following server configuration to your settings.xml:

<servers>
   <server>
      <id>ossrh</id>
      <username>sonatypeuser</username>
      <password>sonatypepassword</password>
   </server>
</servers>

You must also follow the official instructions to create a PGP key to sign the deployed items.

Objenesis supports a wide range of JVMs, including Sun/Oracle Hotspot, OpenJDK, Android, and various specialized JDKs like Azul Zulu and Zing. Compatibility depends on the version of Objenesis you are using:

• Objenesis 1.x: Supports Java 1.3 to 1.7
• Objenesis 2.x: Supports Java 1.5 to 10
• Objenesis 3.x: Supports Java 1.8 to 16

Specific JVM Support Details:

• Android: API level 8 to 30 (Serialization support requires Honeycomb or higher).
• Azul Zulu: Tested on 1.8.0_45-b14.
• Azul Zing JDK 1.8: Tested on 1.8.0-zing_16.10.1.0-b2.
• IKVM: Tested on 8.1.5717.
• BEA JRockit R27, R28: Supported by Objenesis versions < 3.
• GCJ: Version 3.4.4 (tested on Windows/Cygwin).
• PTC Perc: Tested on version 5.0.0667 (Note: No serialization support).