FakeLoad is an open-source Java library which provides developers with a simple way of producing “fake" system loads in their applications.
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FakeLoad is an open-source Java library which provides a simple and flexible way of producing “fake" system loads in applications or tests.

Producing system load using FakeLoad is as simple as this:

// Creation
FakeLoad fakeload = FakeLoads.create()
    .lasting(10, TimeUnit.SECONDS)
    .withMemory(300, MemoryUnit.MB);
// Execution
FakeLoadExecutor executor = FakeLoadExecutors.newDefaultExecutor(); 

The above snippet would simulate a CPU load of 80% and a memory load of 300 MB for ten seconds.


FakeLoad was created with three different use cases in mind:

1. Testing of Non-Functional Requirements

Early verification of non-functional requirements like scalability, performance, availablity, etc. can be vital to a project's success. For example, an application or framework that does elastic data stream processing needs to make sure its auto-scaling behavior or monitoring is working correctly. This can be hard to test if the system is not fully developed yet as some "not yet" implemented parts of the system might have a huge impact on the those dynamic properties.

FakeLoad can be used to simulate system behavior in missing parts. This way, instead of force-implementing missing parts or making risky assumptions about runtime behavior, developers can actually test dynamic properties of their systems.

2. Testing with Test Doubles (a.k.a. Mocks, Fakes, Dummies, etc.)

Replacing real objects with test doubles is a well-established practice in software testing, as they usually help to test components of a software system in isolation. However, replacing real objects with simpler 'fakes' can be dangerous when the simpler 'fake' object doesn't sufficiently mimick the more complex 'real' object or certain parts of it.

FakeLoad can be used to mimick runtime characteristics like CPU usage, etc. within test doubles. As FakeLoad is designed to be easy-to-use, test doubles would remain simple while at the same time mimicking 'real' behavior.

3. Faking of "real" Data or Algorithms

Sometimes NDAs might prohibit publication or scientific evaluation involving certain algorithms or data. FakeLoad can be used to "simulate" data or an algorithm's behavior, bypassing the NDA and thus allowing publication.

Getting Started

You can add a dependency on FakeLoad using Maven with:


To add a dependency using Gradle, use this:

repositories {

dependencies {
    compile 'com.martensigwart:fakeload:0.4.0'


Check out the User Guide for more usage examples and other information. The javadocs can be found here.

How to contribute

FakeLoad was created in the course of a university project so there sure is room for improvements. Feel welcome to file a bug report or submit feature requests through the issue tracker. If you want to contribute feel free to submit a pull request.



This project is licensed under the MIT License - see the LICENCE.md file for details