Multi-layered applications often require to map between different object models (e.g. DTOs and entities). Writing such boiler plate mapping code is a tedious and error-prone task. A lot of object-to-object mapping Java frameworks aims to simplify this work and automate it. Some uses code instrospection (eg. Dozer). Other uses code generation (ex: MapStruct). This micro-benchmark compares performance of 9 frameworks. Results could be compared to the benchmark of a code written manually.

Benchmark are powered by a tool called JMH or also known as "Java Microbenchmarking Harness". JMH is developed by the OpenJDK team.

• Dozer
• MapStruct
• ModelMapper
• Selma
• Orika
• JMapper
• BULL
• datus
• ReMap
• SJF4J

Github is for social coding platform: if you want to add another mapping framework or optimize an existing one, we encourage contributions through pull requests from forks of this repository. If you want to contribute code this way, please reference a GitHub ticket as well covering the specific issue you are addressing. To add a new mapper, please add a unit test that extends the AbstractMapperTest class and declare your mapper into the MapperBenchmark class.

The data model used by this benchmark is very basic. It comes from the Comparison class from the ModelMapper framework. It includes combinations which usually appear in Java Beans, such as:

• Object types
• Collections

Pre-requisites: Maven 3.x and a JDK 17 (or above)

git clone git://github.com/arey/java-object-mapper-benchmark.git

mvn clean install

java @jvm.options -jar target/benchmarks.jar

Optional: To run a single benchmark, such as MapStruct, use java @jvm.options -jar target/benchmarks.jar -p type=MapStruct

The benchmarks measure throughput, given in "ops/time". The time unit used is seconds. Generally, the score represents the number of graph object mapped per second; the higher the score, the better.

Tests has been performed on:

• OS: macOS Tahoe 26.5
• CPU: Apple M4 Pro
• RAM: 24 GB
• JVM: Eclipse Temurin 21.0.5+11

• Micro-benchmark of Java mapping object frameworks (french article)

1. Run benchmark while exporting results to csv with java @jvm.options -jar target/benchmarks.jar -rff results.csv -rf csv
2. Use gnuplot to generate plot with gnuplot benchmark.plt. This will output results.png.

• Uses Maven as a build tool
• Uses JMH for Java Microbenchmarking Harness