Juneau Shaded Artifacts

Juneau provides shaded (uber) JAR artifacts that bundle multiple Juneau modules into single JAR files. These artifacts simplify dependency management and are especially useful for build systems like Bazel that require explicit dependency declarations.

What Are Shaded Artifacts?

Shaded artifacts use the Maven Shade Plugin to:

Bundle multiple Juneau modules into a single JAR
Merge service provider files automatically
Eliminate the need to declare transitive Juneau dependencies
Maintain all original functionality without modification

Important: Shaded artifacts only bundle Juneau modules. External dependencies (like Apache HttpClient, Jakarta Servlet API, etc.) must still be declared separately.

Available Shaded Artifacts

Artifact	Size	Description	Details
juneau-shaded-core	2.0 MB	Core marshalling and configuration functionality	Learn more →
juneau-shaded-rest-client	3.8 MB	Core + REST client functionality	Learn more →
juneau-shaded-rest-server	3.8 MB	Core + REST server functionality	Learn more →
juneau-shaded-rest-server-springboot	3.8 MB	REST server + Spring Boot integration	Learn more →
juneau-shaded-all	4.0 MB	Complete Juneau framework in one JAR	Learn more →

When to Use Shaded Artifacts

✅ Use Shaded Artifacts When:

Using Bazel or similar build systems - These require explicit dependency declarations; shaded artifacts simplify this significantly
Wanting simplified dependency management - One dependency instead of many
Building standalone applications - Uber JARs are convenient for deployment
Getting started quickly - Fewer decisions about which modules to include

❌ Consider Individual Modules When:

Building a library - Other projects may need fine-grained control over dependencies
Minimizing JAR size - Individual modules allow excluding unused functionality
Avoiding classpath conflicts - In complex applications with many dependencies
Needing different module versions - Though this is rarely necessary

Quick Start

Maven

<dependency>
    <groupId>org.apache.juneau</groupId>
    <artifactId>juneau-shaded-all</artifactId>
    <version>${juneau.version}</version>
</dependency>

Bazel

maven_jar(
    name = "juneau_all",
    artifact = "org.apache.juneau:juneau-shaded-all:${juneau.version}",
)

Why Shaded Artifacts for Bazel?

Bazel enforces strict dependency management where you must explicitly declare every direct dependency your code uses. Unlike Maven, which automatically resolves transitive dependencies, Bazel requires you to know and declare all dependencies.

The Problem with Regular Juneau in Bazel

When using regular Juneau modules in Bazel:

# This is incomplete and will fail!
maven_jar(
    name = "juneau_marshall",
    artifact = "org.apache.juneau:juneau-marshall:9.2.0-SNAPSHOT",
)

java_library(
    name = "my_lib",
    srcs = ["MyCode.java"],
    deps = ["@juneau_marshall//jar"],  # Missing juneau-common!
)

Problem: Your code can't compile because juneau-marshall depends on juneau-common, but you didn't declare it.

Solution with Shaded Artifacts

Just one dependency declaration!

maven_jar(
    name = "juneau_core",
    artifact = "org.apache.juneau:juneau-shaded-core:9.2.0-SNAPSHOT",
)

java_library(
    name = "my_lib",
    srcs = ["MyCode.java"],
    deps = ["@juneau_core//jar"],  # Everything included!
)

Complete Bazel Examples

Example 1: REST Client

Scenario: Build a REST client application.

WORKSPACE:

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

# Add Maven dependencies
maven_jar(
    name = "juneau_rest_client",
    artifact = "org.apache.juneau:juneau-shaded-rest-client:9.2.0-SNAPSHOT",
    repository = "https://repository.apache.org/content/repositories/snapshots/",
)

# External dependencies (still need these)
maven_jar(
    name = "httpclient5",
    artifact = "org.apache.httpcomponents.client5:httpclient5:5.2.1",
)

maven_jar(
    name = "httpcore5",
    artifact = "org.apache.httpcomponents.core5:httpcore5:5.2.1",
)

BUILD:

java_binary(
    name = "my_rest_client",
    srcs = ["MyRestClient.java"],
    deps = [
        "@juneau_rest_client//jar",
        "@httpclient5//jar",
        "@httpcore5//jar",
    ],
    main_class = "com.example.MyRestClient",
)

Example 2: REST Server

Scenario: Build a REST server application.

WORKSPACE:

maven_jar(
    name = "juneau_rest_server",
    artifact = "org.apache.juneau:juneau-shaded-rest-server:9.2.0-SNAPSHOT",
    repository = "https://repository.apache.org/content/repositories/snapshots/",
)

maven_jar(
    name = "jakarta_servlet_api",
    artifact = "jakarta.servlet:jakarta.servlet-api:6.1.0",
)

maven_jar(
    name = "jetty_server",
    artifact = "org.eclipse.jetty:jetty-server:12.0.5",
)

BUILD:

java_library(
    name = "my_rest_server",
    srcs = ["MyRestServer.java"],
    deps = [
        "@juneau_rest_server//jar",
        "@jakarta_servlet_api//jar",
        "@jetty_server//jar",
    ],
)

Example 3: Spring Boot Integration

Scenario: Build a Spring Boot + Juneau application.

WORKSPACE:

maven_jar(
    name = "juneau_rest_server_springboot",
    artifact = "org.apache.juneau:juneau-shaded-rest-server-springboot:9.2.0-SNAPSHOT",
    repository = "https://repository.apache.org/content/repositories/snapshots/",
)

maven_jar(
    name = "spring_boot_starter_web",
    artifact = "org.springframework.boot:spring-boot-starter-web:3.2.0",
)

BUILD:

java_library(
    name = "my_spring_app",
    srcs = glob(["src/**/*.java"]),
    deps = [
        "@juneau_rest_server_springboot//jar",
        "@spring_boot_starter_web//jar",
    ],
)

Example 4: Core Marshalling Only

Scenario: Use Juneau for JSON/XML/etc. serialization without REST features.

WORKSPACE:

maven_jar(
    name = "juneau_core",
    artifact = "org.apache.juneau:juneau-shaded-core:9.2.0-SNAPSHOT",
    repository = "https://repository.apache.org/content/repositories/snapshots/",
)

BUILD:

java_library(
    name = "my_serialization_lib",
    srcs = ["MySerializer.java"],
    deps = [
        "@juneau_core//jar",
    ],
)

Example 5: Everything (Complete Framework)

Scenario: You want access to all Juneau features.

WORKSPACE:

maven_jar(
    name = "juneau_all",
    artifact = "org.apache.juneau:juneau-shaded-all:9.2.0-SNAPSHOT",
    repository = "https://repository.apache.org/content/repositories/snapshots/",
)

# Still need external dependencies
maven_jar(
    name = "jakarta_servlet_api",
    artifact = "jakarta.servlet:jakarta.servlet-api:6.1.0",
)

maven_jar(
    name = "httpclient5",
    artifact = "org.apache.httpcomponents.client5:httpclient5:5.2.1",
)

BUILD:

java_library(
    name = "my_full_app",
    srcs = glob(["src/**/*.java"]),
    deps = [
        "@juneau_all//jar",
        "@jakarta_servlet_api//jar",
        "@httpclient5//jar",
    ],
)

Finding External Dependencies

Shaded JARs only bundle Juneau modules. External dependencies (like Apache HttpClient, Jakarta Servlet API, etc.) must still be declared separately.

Method 1: Check the dependency-reduced-pom.xml

After building a shaded module, examine:

cat juneau-shaded/juneau-shaded-rest-client/dependency-reduced-pom.xml

This file lists all external dependencies that the shaded JAR still requires.

Method 2: Use Maven dependency:tree

cd juneau-shaded/juneau-shaded-rest-client
mvn dependency:tree

Method 3: Common External Dependencies

Here's a quick reference:

Juneau Shaded Artifact	Common External Dependencies
`juneau-shaded-core`	None
`juneau-shaded-rest-client`	`httpclient5`, `httpcore5`
`juneau-shaded-rest-server`	`jakarta.servlet-api`, `jetty-server`
`juneau-shaded-rest-server-springboot`	`spring-boot-starter-web`, `jakarta.servlet-api`
`juneau-shaded-all`	All of the above

Advanced: Using rules_jvm_external

For more sophisticated Bazel builds, use rules_jvm_external:

WORKSPACE:

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

RULES_JVM_EXTERNAL_TAG = "5.3"
RULES_JVM_EXTERNAL_SHA = "d31e369b854322ca5098ea12c69d7175ded971435e55c18dd9dd5f29cc5249ac"

http_archive(
    name = "rules_jvm_external",
    strip_prefix = "rules_jvm_external-%s" % RULES_JVM_EXTERNAL_TAG,
    sha256 = RULES_JVM_EXTERNAL_SHA,
    url = "https://github.com/bazelbuild/rules_jvm_external/releases/download/%s/rules_jvm_external-%s.tar.gz" % (RULES_JVM_EXTERNAL_TAG, RULES_JVM_EXTERNAL_TAG),
)

load("@rules_jvm_external//:defs.bzl", "maven_install")

maven_install(
    artifacts = [
        "org.apache.juneau:juneau-shaded-rest-client:9.2.0-SNAPSHOT",
        "org.apache.httpcomponents.client5:httpclient5:5.2.1",
        "org.apache.httpcomponents.core5:httpcore5:5.2.1",
    ],
    repositories = [
        "https://repository.apache.org/content/repositories/snapshots/",
        "https://repo1.maven.org/maven2",
    ],
    fetch_sources = True,
)

BUILD:

java_binary(
    name = "my_app",
    srcs = ["MyApp.java"],
    deps = [
        "@maven//:org_apache_juneau_juneau_shaded_rest_client",
        "@maven//:org_apache_httpcomponents_client5_httpclient5",
        "@maven//:org_apache_httpcomponents_core5_httpcore5",
    ],
    main_class = "com.example.MyApp",
)

Bazel Troubleshooting

Build fails with "package X does not exist"

Cause: You're missing an external dependency.

Solution: Check the dependency-reduced-pom.xml for the shaded module and add the missing dependency to your WORKSPACE.

Conflicting versions of dependencies

Cause: Multiple artifacts depend on different versions of the same library.

Solution: Use rules_jvm_external with version resolution:

maven_install(
    artifacts = [
        "org.apache.juneau:juneau-shaded-rest-client:9.2.0-SNAPSHOT",
        "org.apache.httpcomponents.client5:httpclient5:5.2.1",
    ],
    version_conflict_policy = "pinned",  # Use specific versions
)

Shaded JAR is too large

Cause: You're using juneau-shaded-all when you only need a subset.

Solution: Use a more specific shaded artifact:

For client only: juneau-shaded-rest-client
For server only: juneau-shaded-rest-server
For core only: juneau-shaded-core

Bazel Best Practices

Start with the smallest shaded artifact that meets your needs
Always check dependency-reduced-pom.xml for external dependencies
Use rules_jvm_external for production Bazel builds
Pin dependency versions to ensure reproducible builds
Document external dependencies in your project's README

Performance Considerations

Build Time

Shaded JARs: Faster builds due to fewer dependency declarations
Individual Modules: More explicit control but slower due to transitive resolution

Runtime

No runtime difference between shaded and non-shaded artifacts
Same classes, same performance characteristics

JAR Size

Shaded JARs are larger but self-contained
For microservices, this is usually acceptable
For libraries, consider using individual modules

Architecture

The shaded modules form a dependency hierarchy:

juneau-shaded-core (2.1 MB)
    ↓
    ├─→ juneau-shaded-rest-client (3.8 MB)
    │
    └─→ juneau-shaded-rest-server (3.8 MB)
            ↓
            └─→ juneau-shaded-rest-server-springboot (3.8 MB)

juneau-shaded-all (4.0 MB)
    = juneau-shaded-rest-server-springboot
    + juneau-rest-client
    + all bean modules
    + all microservice modules

Distribution

All shaded artifacts are included in the binary distribution under the /shaded directory:

apache-juneau-${version}-bin.zip
└── shaded/
    ├── juneau-shaded-core-${version}.jar
    ├── juneau-shaded-rest-client-${version}.jar
    ├── juneau-shaded-rest-server-${version}.jar
    ├── juneau-shaded-rest-server-springboot-${version}.jar
    └── juneau-shaded-all-${version}.jar

Learn More

Individual Shaded Artifacts

Juneau Shaded Core - Core marshalling and configuration
Juneau Shaded REST Client - REST client development
Juneau Shaded REST Server - REST server development
Juneau Shaded REST Server Spring Boot - Spring Boot integration
Juneau Shaded All - Complete framework

Additional Resources

Shaded Module README - Complete technical documentation
Juneau Documentation - Official Juneau docs
Bazel Documentation - Learn more about Bazel
Apache Juneau Mailing List - Get help from the community

What Are Shaded Artifacts?​

Available Shaded Artifacts​

When to Use Shaded Artifacts​

✅ Use Shaded Artifacts When:​

❌ Consider Individual Modules When:​

Quick Start​

Maven​

Bazel​

Why Shaded Artifacts for Bazel?​

The Problem with Regular Juneau in Bazel​

Solution with Shaded Artifacts​

Complete Bazel Examples​

Example 1: REST Client​

Example 2: REST Server​

Example 3: Spring Boot Integration​

Example 4: Core Marshalling Only​

Example 5: Everything (Complete Framework)​

Finding External Dependencies​

Method 1: Check the dependency-reduced-pom.xml​

Method 2: Use Maven dependency:tree​

Method 3: Common External Dependencies​

Advanced: Using rules_jvm_external​

Bazel Troubleshooting​

Build fails with "package X does not exist"​

Conflicting versions of dependencies​

Shaded JAR is too large​

Bazel Best Practices​

Performance Considerations​

Build Time​

Runtime​

JAR Size​

Architecture​

Distribution​

Learn More​

Individual Shaded Artifacts​

Additional Resources​

What Are Shaded Artifacts?

Available Shaded Artifacts

When to Use Shaded Artifacts

✅ Use Shaded Artifacts When:

❌ Consider Individual Modules When:

Quick Start

Maven

Bazel

Why Shaded Artifacts for Bazel?

The Problem with Regular Juneau in Bazel

Solution with Shaded Artifacts

Complete Bazel Examples

Example 1: REST Client

Example 2: REST Server

Example 3: Spring Boot Integration

Example 4: Core Marshalling Only

Example 5: Everything (Complete Framework)

Finding External Dependencies

Method 1: Check the dependency-reduced-pom.xml

Method 2: Use Maven dependency:tree

Method 3: Common External Dependencies

Advanced: Using rules_jvm_external

Bazel Troubleshooting

Build fails with "package X does not exist"

Conflicting versions of dependencies

Shaded JAR is too large

Bazel Best Practices

Performance Considerations

Build Time

Runtime

JAR Size

Architecture

Distribution

Learn More

Individual Shaded Artifacts

Additional Resources