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OPC Foundation UA JAVA Legacy

This repository is provided by OPC Foundation as legacy support for an Java version for OPC UA. It will not receive further features and updates.

The OPC Foundation will continue maintenance of the .NET Stack which is based on .NET Standard. It can be found here.

The OPC Foundation has formally released the Unified Architecture Java Stack and Sample Code to the community.

Please review official site page ( for:

  • Overview
  • Licensing
  • Sample Applications overview

Recommended Development Environment

Note these are recommended, earlier versions might work.

  • Eclipse 4.5.2 (Mars)
  • Maven 3.3.3 (included in Eclipse 4.5.2)
  • JDK 8
  • JDK 6, in case you want to be sure that the built jar is java 6 compatible

The JDK(s) must have the sunjce_provider, e.g. use Oracle or OpenJDK (because the stack has optional support for the sun jce crypto provider)

Runtime Dependencies

The Stack requires Java SE 6 or later to run (for building requirements, see under 'Building the Stack').

See pom.xml for details about dependency jar versions.

The following dependencies are mandatory

  • org.slf4j, SLF4J logging facade

Additionally the following dependencies are optional

  • org.bouncycastle, Bouncy Castle, for using bouncy castle crypto provider (see 'Security' section)
  • com.madgag.spongycastle, Spongy Castle, for using spongycastle crypto provider (used in android, See 'Security' section)
  • org.apache.httpcomponents, HTTPS support libs, for https transport protocol support

Library licenses are in the license-directory. All Apache libraries use the Apache License 2.0. Bouncy Castle and Spongy Castle use the Bouncy Castle License.

Building the Stack

As of 1.03 the project is a maven project.

Note that the built jar will be only compatible for the java version it is built with (see the section 'Building Java 6 compatible release' for more information).


  • Import the project in your favorite IDE
  • e.g. in Eclipse Import->Existing Maven
  • Execute the 'package' phase.

Alternatively assuming you have Maven installed and in PATH, you can build from the command line:

mvn package

The resulting artifacts are in the 'target' folder

  • opc-ua-stack-XXX.jar, the main jar
  • opc-ua-stack-XXX-javadoc.jar, javadoc documentation
  • opc-ua-stack-XXX-sources.jar, sources
  •, zip of this project (without build artifacts)
  •, zip of the project dependencies

Building Java 6 compatible release

If you want to be sure the built jar is Java 6 compatible, you need to install a Java 6 JDK. In addition, because newest maven versions require at least Java 7, you need to also install it (or later) too.

The reason for requiring a version 6 of the JDK is that, while some newer versions of JDK have support for compiling to older versios of Java it is not enough to just define the source and the target arguments to 1.6. In addition a bootstrapclasspath argument needs to be defined (and pointed to a Java 6 installation) in order to use correct versions of the standard java libraries. Another option is using the older JDK version to compile by using maven-toolchains-plugin, which this project uses. It should also make this more future proof in case future JDK versions drop support for target 1.6, with JDK 9 being the last to support it (see

You need to activate profile 'jdk6' to use the toolchains plugin.

Maven needs to know where your JDK 6 installation is. To setup this create a file 'toolchains.xml' in your .m2 folder (which exists in your home folder) with the following contents:

	  <jdkHome>ABSOLUTE PATH TO JAVA 6 JDK HOME</jdkHome>

If you have no need to have a Java 6 supported build artifact, then you can run the build with the jdk6 profile disabled.


The 'examples' folder has a separate maven project that contains the samples, it has a dependency to the main stack project. See the examples/ for more information.

Notes for developers

The stack codegen is provided under the 'codegen' folder. See codegen/ for more information

Package file structure description

See generated javadoc after building, or files in each package

Mappings between Java and OPC UA types

See the javadoc for package


Security libraries are used as they are available. If no extra libraries are available, the Sun JCE implementation will be used. Testing has so far based on the Bouncy Castle library and it is therefore recommended in normal applications.

The current implementation, since version 1.02.337.0, is based on a flexible CryptoProvider model. There are several implementations of this interface available in the stack and you can also implement your own, if you have a custom security framework that you need to use.

The stack will pick a default CryptoProvider automatically as it finds them from the class path. Alternatively, you can define the provider that you wish to use by setting it with CryptoUtil.setCryptoProvider() or with CryptoUtil.setSecurityPoviderName().

In the same manner, custom certificate framework can be used by implementing interface CertificateProvider and setting it with CertificateUtils.setCertificateProvider().

Current CryptoProvider implementations:

BcCryptoProvider (default, if Bouncy Castle is in the class path: uses Bouncy Castle directly) ScCryptoProvider (default in Android, if Spongy Castle is in the class path) SunJceCryptoProvider (default if Bouncy Castle or Spongy Castle are not available) BcJceCryptoProvider (uses Bouncy Castle via the JCE crypto framework) ScJceCryptoProvider (uses Spongy Castle via the JCE crypto framework)

If any of the ...JceCryptoProvider is used, you will have to install the JCE Unlimited Strength Jurisdiction Policy Files, from Oracle (for Java 6, 7 or 8, respectively), to enable support for 256 bit security policies:


Android includes a limited version of Bouncy Castle and the standard Bouncy Castle cannot be installed there. It also does not include the Sun classes. However, the Spongy Castle libraries will provide the same functionality as Bouncy Castle in Android, so these libraries should be used in Android, unless the application can do without security altogether.

Current CertificateProvider implementations:

BcCertificateProvider (default, if Bouncy Castle is in the class path) ScCertificateProvider (default in Android, if Spongy Castle is in the class path) SunJceCertificateProvider (default if Bouncy Castle or Spongy Castle are not available)

Known issues

  • TLS 1.2 policy required by OPC UA does not work (required ciphers not supported by JSSE)
  • HTTPS testing is not finished yet with the other stacks
  • .NET Client requires that the server has a certificate signed by a trusted CA, if HTTPS is used. See 'examples/'.


This repository is provided by OPC Foundation as legacy support for an Java version for OPC UA.







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