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Bridge Java and .NET Without Migration

.NET and Java power a large share of the software in production today. When a project needs both, the traditional answers are costly rewrites, REST APIs with their network overhead, or migrations that take months and break things along the way — each introducing new attack surfaces and integration points that need to be secured.

JCOBridge takes a different approach: direct in-process integration over JNI. No network exposure, no serialization layer, no external channels to harden. The security perimeter stays where it already is.

Why JCOBridge?

Support legacy systems — Java 8 through 25 fully supported. Integrate without upgrading: a modern JVM runs older bytecode seamlessly, so proven systems stay untouched.

True in-process integration — JNI-based communication, not REST or gRPC. No copies, no channels, no overhead that doesn’t need to exist.

Maximize code reuse — share libraries across Java and .NET teams, access Java-only components from .NET, modernize incrementally without big-bang rewrites.

Common Use Cases:

  • 🏦 Finance: Integrate Java 8 core banking with .NET fraud detection
  • 🏭 Manufacturing: Bridge Java MES systems with .NET cloud analytics
  • 🏛️ Government: Modernize certified Java 8 apps without recertification
  • 📊 Data & AI: Add ML.NET AI to existing Java applications

Explores available features or go directly to the getting started page.

Advantages and Benefits

⭐ Now Supporting Java 8

Legacy Integration Without Migration

70% of enterprises still run Java 8 in production. JCOBridge enables integration with modern .NET applications without requiring costly Java upgrades — keeping proven, stable systems running while gaining access to the full .NET ecosystem.

  • ✅ No changes to existing Java code (8+)
  • ✅ Deploy in weeks instead of months
  • ✅ Low risk – stable systems stay stable
  • ✅ No forced Java upgrade to benefit from modern .NET
Learn About Java 8 Integration →
Supported Java Versions
☕ Java 8 (2014-2030) ⭐
☕ Java 11 (LTS)
☕ Java 17 (LTS)
☕ Java 21 (LTS)
☕ Java 25 (LTS)

Oracle Extended Support until Dec 2030

Fast &
Cyber-safe

Fast and Cyber-safe by design: no marshalling, no proxies, no custom channels. Nothing between .NET and JVM but the JNI boundary itself — the shortest and safest path by architecture.

Minimize
TTM

Eliminate long and risky software portings. JCOBridge lets you use your existing Java code from .NET applications — and vice versa — without rewriting a line. Ship faster, with less to go wrong.

Reuse
code

A working software library is an asset — it should run everywhere. JCOBridge lets you bring your existing Java or .NET codebase into any project, on any supported platform, without duplication.

Avoid
staffing

When a project needs to target a different platform, the usual answer is hiring or retraining. With JCOBridge you develop in your reference platform and deploy where the customer needs it — without expanding the team.

Save
money

Every migration project carries a budget, a timeline, and a risk of breaking what was working. JCOBridge removes the need for migration entirely: integrate across platforms instead of rewriting for them. The cost of integration is a fraction of the cost of porting.

Reduce
risks

The less code you rewrite, the less you can break. JCOBridge keeps your existing Java and .NET codebases intact, limiting the surface area for regressions, security issues, and unexpected behavior in production.

Increase
market

Two of the largest ecosystems in software development — .NET and JVM — have historically required separate teams, separate codebases, separate products. JCOBridge collapses that divide. One codebase, both markets.

Versions and Features

Version 2.5.*

  • Support .NET 4.6.2+, 6, 8 (2.5.9+) and 9 (2.5.18+)
    • .NET 6, 8 and 9 host for Windows, Linux and MacOS (current unsupported platforms are available on demand)
    • .NET 7 removed from version 2.5.12
    • Windows ARM removed in .NET 6 (2.5.18+), 8 (2.5.14+)
    • Added MacOS from version 2.5.15, 2.5.18+ supports only MacOS 13+
  • Support any JVM 11+
  • Simplified wrapping of Java classes from .NET
  • Speed improvements by 40%
  • License model upgrade to actively support community: it is possible to use online requests together with file based licensing
  • Other features

Version 2.6.*

  • Support .NET 4.6.2+, 8, 9 and 10: .NET 8/9/10 host for Windows, Linux and MacOS (current unsupported platforms are available on demand)
  • Support any JVM from 8 to latest
  • Simplified wrapping of Java classes from .NET
  • Speed improvements by 40%
  • License model reviewed to better support community: the product can be used without restrictions if its usage does not produce any income
  • Other features

Version 3.0.*

JCOBridge 3.0 is currently in development — a full re-engineering of the core bridge layer.

  • Will support .NET 4.6.2+ and .NET 8+
  • Support any JVM from 8 to latest
  • Other features

Products

JCOBridge Core

The main core engine is available on

Explore some products based on JCOBridge

.NET Products

JNet

The github repository contains the full disclosed source of JNet: Java/JVM suite for .NET. A comprehensive suite of libraries and tools to use Java/JVM APIs (Java, Scala, Kotlin, …) and .NET side-by-side.

Go to repo

KNet

The github repository contains the full disclosed source of KNet: The Apache Kafka .NET suite. KNet is a comprehensive .NET suite for Apache Kafka providing all features: Producer, Consumer, Admin, Streams, Connect, backends (ZooKeeper and Kafka).

Go to repo

KNet OPC

The Apache Kafka connector for OPC-UA protocol, it is based on KNet Connect SDK.

Ask more info

KEFCore

The github repository contains the full disclosed source of KEFCore: the EntityFrameworkCore provider for Apache Kafka based on KNet.

Go to repo

NetPDF

The github repository contains the full disclosed source of NetPDF: the PDFBox suite for .NET.

Go to repo

JVM Products

JCOReflector

The github repository contains the full disclosed source of JCOReflector: a tool able to reflect .NET classes in Java (JVM) to simplify the use of .NET from Java or any other JVM enabled language.

Go to the repo

NuReflector

The github repository contains the full disclosed source of NuReflector: a tool able to produce Maven artifacts from NuGet packages. It is based on JCOReflector Engine.

Go to the repo

Public support information

GitHub

The github repository is the new public site where public issues can be reported.

Go to issues

Stack Overflow

Public questions can be requested on Stack Overflow site: use the tag #jcobridge within your question.

Go to…