Compare performance Dozer vs MapStruct

This little project tests performance of mapping using Dozer and MapStruct. First it creates 1 000 000 objects "Worker" and than using each library maps it into "WorkerInfo" objects.

Test results

Running on my notebook:

• Intel® Core™ i7-3630QM CPU @ 2.40GHz × 8
• 16GB RAM
• SDD
• Ubuntu 15.10 (64-bit)
• Java(TM) SE Runtime Environment (build 1.8.0_72-b1)

INFO  Main:36 - Preparing sample data...
INFO  Main:43 - Done preparing sample data in 2.59300 seconds
INFO  Main:61 - Start mapping with MapStruct...
INFO  Main:68 - Mapping with MapStruct done in 3.51100 seconds
INFO  Main:48 - Start mapping with Dozer...
INFO  Main:56 - Mapping with Dozer done in 16.28200 seconds

Comparison points are here:

Points	Dozer	MapStruct
Description	Mapping rules are defined in XML files, which are then loaded during application runtime. Dozer is using reflection mechanism for mapping	Mapping rules are defined in Java files, mostly in annotations. Based on this rules MapStruct generates Java classes, which are then used for mapping
Speed	Dozer uses reflection mechanism for mapping, which means it is slower than MapStruct. In example (link) it is mapped 1 000 000 objects. On my notebook it takes about 16 seconds	MapStruct invoke methods of classes, which were generated before compilation. Thanks to that it works faster than Dozer. In example (link) it is mapped 1 000 000 objects. On my notebook it takes about 3 seconds. #### MapStruct is about 500% faster than Dozer
Security	When you make a mistake in XML that contains mapping rules you will know about it only during invoking mapping (runtime error).	When you make a mistake in property name, you will know about it during compilation. Thanks that application will be more reliable
Immutable objects	Dozer can access private properties (by reflection). It makes possible to map immutable objects which haven’t setters. It requires that immutable object has a constructor without parameters and in mapping files you should add attribute is-accessible="true" to destination fields	Unfortunately MapStruct hasn’t ability to map immutable objects. There is an open issue(mapstruct/mapstruct#73) about that.
Debugging	Mapping rules are defined mostly in XML files. During application runtime that files are loaded. Thus debugging mapping process is difficult – you have to set breakpoints in Dozer classes	You can set breakpoint in classes, which was generated during compilation. Thanks that you can easily determine which classes are used for mapping and debug them.
Popularity (as at the date 23.03.2016)	Creation date: 04.06.2005 Stackoverflow: 1610 postów Github: https://github.com/DozerMapper/dozer Last release date: 22.04.2014	Creation date: 22.05.2012 Stackoverflow: 108 postów Github: https://github.com/mapstruct/mapstruct Last release date: 16.03.2016
Debugging	Mapping rules are defined mostly in XML files. During application runtime that files are loaded. Thus debugging mapping process is difficult – you have to set breakpoints in Dozer classes.	You can set breakpoint in classes, which was generated during compilation. Thanks that you can easily determine which classes are used for mapping and debug them.
Additional advantages	nothing special	a. More default mapping for example: Joda-Time, JAXBElement b. Mapping code only in Java files – faster determination, which code is responsible for data mapping. c. Event handling (@BeforeMapping, @AfterMapping) d. Built-in support for decorators

Run it locally

mvn install exec:java -pl mapper -DskipTests

More information Dozer vs MapStruct

http://mariusz.wyszomierski.pl/en/mapping-dozer-vs-mapstruct/