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bytedeco
javacpp
Java2016–2021
bytedeco / javacpp

javacpp

The missing bridge between Java and native C++

6Distinct people
19Mentions
0Explicit recommenders
4.7KGitHub stars
REPOSITORY AT A GLANCE

What to know before exploring

What it is

The missing bridge between Java and native C++

GitHub

Where it is used

No documented product use has been verified yet.

What people are saying

No recommendation phrase was found in the indexed comments.

No classified warning is attached to this page. Read the discussions before treating silence as approval.

Also in these discussions

Mentioned in the same Hacker News threads. That is not proof they are substitutes.

This week on Hacker News

Nov 8–Nov 15 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/15/2026, 2:59:58 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year19 dated mentions

Observed mentions: 2016-02-13 15:43:24 UTC to 2021-03-25 14:58:56 UTC.

02468102016-01-01 00:00:00 UTC to 2017-01-01 00:00:00 UTC (exclusive): 9 mentions; 1 submissions, 8 comments20162017-01-01 00:00:00 UTC to 2018-01-01 00:00:00 UTC (exclusive): 4 mentions; 0 submissions, 4 comments2018-01-01 00:00:00 UTC to 2019-01-01 00:00:00 UTC (exclusive): 3 mentions; 0 submissions, 3 comments20182019-01-01 00:00:00 UTC to 2020-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2020-01-01 00:00:00 UTC to 2021-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2021-01-01 00:00:00 UTC to 2022-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2021

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
20162016-01-01 00:00:00 UTC2017-01-01 00:00:00 UTC918
20172017-01-01 00:00:00 UTC2018-01-01 00:00:00 UTC404
20182018-01-01 00:00:00 UTC2019-01-01 00:00:00 UTC303
20192019-01-01 00:00:00 UTC2020-01-01 00:00:00 UTC101
20202020-01-01 00:00:00 UTC2021-01-01 00:00:00 UTC101
20212021-01-01 00:00:00 UTC2022-01-01 00:00:00 UTC101

What Hacker News says

9 sources
Nah I mean this stuff IS hard. That's why I offered that mailing list. Like I said a lot of people from azul and a lot of the hardcore jvm heads sit on there. If there's a way to make java faster for that great. You are are right that the jvm DOES support some of the tight loop stuff. It's harder to do and leads to messy code though. In C++ you can write maintainable code and add pragmas. It's a lot cleaner and with javacpp (https://github.com/bytedeco/javacpp) we just generate the jni bindings. We found that to be easier in practice. I'm admittedly not THAT familiar with the jvm internals. I have just tried to get it to work and have did enough reading to know jni will just be cleaner for that stuff. The JVM is certainly fast enough, just mainly for distributed systems code (eg: databases, message queues) Honestly that's what makes it ap
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pealing for me. I can write fast production systems and tweak it where necessary for the HPC apps. Java provides a fast and safe baseline for 90% of the stuff I'd want it to do. We tried for about a year to get it to work for lin alg and finally said screw it let's just do c++.
In 135M messages a second between processes in Java (2013)
We do scientific computing on the jvm (mainly deep learning). We wrote: https://nd4j.org which immitates numpy and co on the jvm with builtin gpu support and linking against blas like other frameworks. We also hand implemented a lot of ufuncs for you in c++. It's mainly oriented towards dense atm though. Sparse will come at some point but it hasn't been a big feature for us. It uses: https://github.com/bytedeco/javacpp underneath. Happy to answer questions!
In 135M messages a second between processes in Java (2013)
TensorFlow has kind of won the Python deep-learning community, although frameworks like Keras[0] make it easier to use. While Python programmers make up the majority of deep-learning practitioners, they don't have much penetration in enterprise, which is chiefly JVM and lower-level languages. Deeplearning4j [1] has won deep learning on the JVM. Nothing else comes close. (Disclosure: I'm one of its creators.) DL4J has the most sophisticated Spark integration, plugs into Kafka and works as a Hadoop job. It does all that while running on distributed GPUs, multiple CPUs and heterogenous hardware. It wraps cuDNN, which is faster than Tensorflow. Finally, part of our stack, JavaCPP [2], is used by the TF communities as well as other big company projects to bridge the gap between Java and C++. Dev mindshare in the form of Github stars doesn't eq
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ual revenue. Finally, there are a number of strategic problems companies face when adopting a Google project. First, they are leery of depending on Google when they also compete with it. This is particularly true because Google doesn't open source a lot of its best work, like code from DeepMind. So Tensorflow adopters are getting the leftovers in a way, and they're kneecapped in the AI race. Secondly, Tensorflow is not platform neutral. It's optimized for TPUs, which are not publicly available. It's a play to attract people to the Google Cloud. [0] http://keras.io/ [1] http://deeplearning4j.org/ [2] https://github.com/bytedeco/javacpp
In Google Sprints Ahead in AI Building Blocks, Leaving Rivals Wary

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