Lock free ListenableFuture / Future implementation

The project implements java concurrent Future in very cheap and flexible way.

The performance is for obvious reasons (additional support of listeners) slightly lower than original JDK Future but significantly higher than similar implementations in Guava and Spring.


Additionally it solves several design issues from which suffer Guava and Spring implementations:


The performance comparison looks like (measured on my low voltage i7 x86_64):

No listener

Benchmark                                    Mode  Cnt    Score   Error  Units
NoListenerAsyncBenchmark.benchmarkGuava     thrpt    2  157.510          ops/s
NoListenerAsyncBenchmark.benchmarkJdk       thrpt    2  241.154          ops/s
NoListenerAsyncBenchmark.benchmarkLwFuture  thrpt    2  279.774          ops/s
NoListenerAsyncBenchmark.benchmarkSpring    thrpt    2  117.028          ops/s

It's 78% faster than Guava, 139% faster than Spring and 16% faster than JDK.

Single listener set prior to run

Benchmark                                           Mode  Cnt    Score   Error  Units
SinglePreListenerAsyncBenchmark.benchmarkGuava     thrpt    2   98.639          ops/s
SinglePreListenerAsyncBenchmark.benchmarkJdk       thrpt    2  239.813          ops/s
SinglePreListenerAsyncBenchmark.benchmarkLwFuture  thrpt    2  204.984          ops/s
SinglePreListenerAsyncBenchmark.benchmarkSpring    thrpt    2   82.673          ops/s

It's 108% faster than Guava, 148% faster than Spring and 15% slower than JDK (but JDK test runs without listener).


Currenty there are three implementations that differ in details how to handle atomic operations. The performance difference is about 10% but may change with JRE version:


The code is released under version 2.0 of the Apache License.

Stay in Touch

Feel free to contact me at kvr@centrum.cz or http://kvr.znj.cz/software/java/ListenableFuture/ and http://github.com/kvr000