nuclio Java SDK

Java SDK for nuclio.

This SDK is for building nuclio Java handlers.

Adding as a dependency

See https://search.maven.org/artifact/io.nuclio/nuclio-sdk-java/1.2.0/jar

Building a Handler

To implement a handler you need to write a class the implements io.nuclio.EventHandler.

nuctl build does the following logic, depends on the value of -p:

• If it's a jar, use it
• If it's a directory and there's handler.jar there, use it
• If it's a directory with only single jar (including sub directories), use it
• If there's a build.gradle file there - run nuclioJar task and use jar from build directory
• If there's no build.gradle, generate one, build and use jar from build directory

Build will work also if the path passed is a single Java file.

You can specify dependencies using (inline in Java file or Jar) build configuration

// @nuclio.configure
//
// function.yaml:
//   spec:
//     build:
//       dependencies:
//         - group: com.google.code.gson"
//           name: gson"
//           version: 2.8.2"
//         - group: com.google.guava"
//           name: guava"
//           version: 23.6-jre"

The default image uses Eclipse Temurin (OpenJDK) 25. The Java runtime is not supported on 32-bit ARM (armhf) — no upstream Temurin 25 build exists for that architecture.

If you have dependencies in other packages, create a fat/uber Jar with all the dependencies. We currently do not support maven/sbt/ant/... builds

Building the SDK

./gradlew jar

The SDK jar is compiled for Java 25 bytecode. Build it with JDK 25+.