How to use "PropertiesMergingResourceTransformer" of maven-shade-plugin when adding SpringBoot configuration as <dependencyManagement> tag

Question

I am using maven-shade-plugin along with Sprint Boot. I have defined spring-boot dependencies as:

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-dependencies</artifactId>
            <version>2.0.2.RELEASE</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

I already have my project specific uber-pom defined in <parent> tag of my pom.xml so not able to use spring-boot-starter-parent in <parent> tag.

Now, when I do mvn clean install , I get below exception:

`[ERROR] Failed to execute goal org.apache.maven.plugins:maven-shade-plugin:3.1.1:shade (default) on project myapp: Unable to parse configuration of mojo org.apache.maven.plugins:maven-shade-plugin:3.1.1:shade for parameter transformers: Cannot load implementation hint 'org.springframework.boot.maven.PropertiesMergingResourceTransformer'`, 

which clearly says implementation of PropertiesMergingResourceTransformer cannot be found. If I use Spring-boot configuration as defined in <parent> tag, it works fine.

However, if I completely remove PropertiesMergingResourceTransformer configuration in maven-shade-plugin configuration, then bundled jar cannot be executed, and give exception as below:

`java.lang.IllegalArgumentException: No auto configuration classes found in META-INF/spring.factories. If you are using a custom packaging, make sure that file is correct.
    at org.springframework.util.Assert.notEmpty(Assert.java:450) ~[myapp-1.0-SNAPSHOT.jar:na]
    at org.springframework.boot.autoconfigure.AutoConfigurationImportSelector.getCandidateConfigurations(AutoConfigurationImportSelector.java:160) ~[myapp-1.0-SNAPSHOT.jar:na]
    at org.springframework.boot.autoconfigure.AutoConfigurationImportSelector.selectImports(AutoConfigurationImportSelector.java:96) ~[myapp-1.0-SNAPSHOT.jar:na]`

Can somebody help in this.

For reference: This is the maven-shade-plugin issue which was resolved: https://github.com/spring-projects/spring-boot/issues/11200

But it seems to work only if spring-boot dependencies are configured in <parent> tag and not in <dependencyManagement>

While trying to use spring-boot-maven-plugin I get below exception while running the jar:

`Exception in thread "main" java.lang.IllegalStateException: Failed to get nested archive for entry BOOT-INF/lib/spring-boot-2.0.2.RELEASE.jar
    at org.springframework.boot.loader.archive.JarFileArchive.getNestedArchive(JarFileArchive.java:108)
    at org.springframework.boot.loader.archive.JarFileArchive.getNestedArchives(JarFileArchive.java:86)
    at org.springframework.boot.loader.ExecutableArchiveLauncher.getClassPathArchives(ExecutableArchiveLauncher.java:70)
    at org.springframework.boot.loader.Launcher.launch(Launcher.java:49)
    at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51)
Caused by: java.io.IOException: Unable to open nested jar file 'BOOT-INF/lib/spring-boot-2.0.2.RELEASE.jar'
    at org.springframework.boot.loader.jar.JarFile.getNestedJarFile(JarFile.java:254)
    at org.springframework.boot.loader.jar.JarFile.getNestedJarFile(JarFile.java:239)
    at org.springframework.boot.loader.archive.JarFileArchive.getNestedArchive(JarFileArchive.java:103)
    ... 4 more
Caused by: java.lang.IllegalStateException: Unable to open nested entry 'BOOT-INF/lib/spring-boot-2.0.2.RELEASE.jar'. It has been compressed and nested jar files must be stored without compression. Please check the mechanism used to create your executable jar file
    at org.springframework.boot.loader.jar.JarFile.createJarFileFromFileEntry(JarFile.java:282)
    at org.springframework.boot.loader.jar.JarFile.createJarFileFromEntry(JarFile.java:262)
    at org.springframework.boot.loader.jar.JarFile.getNestedJarFile(JarFile.java:250)
    ... 6 more`

Answer 1

Hopefully, you have solved this issue by now, but after banging my head for a few hours with the same problem, I realised the inclusion of spring-boot-maven-plugin as a dependency of maven-shade-plugin is required:

<groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-shade-plugin</artifactId>
            <version>${maven-shade-plugin.version}</version>
            <dependencies>
                <dependency>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                    <version>${spring-boot.version}</version>
                </dependency>
            </dependencies>
            <executions>
                <execution>
                    <phase>package</phase>
                    <goals><goal>shade</goal></goals>
                    <configuration>
                        <transformers>
                            <transformer
                                    implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
                                <resource>META-INF/spring.handlers</resource>
                            </transformer>
                            <transformer
                                    implementation="org.springframework.boot.maven.PropertiesMergingResourceTransformer">
                                <resource>META-INF/spring.factories</resource>
                            </transformer>
                            <transformer
                                    implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
                                <resource>META-INF/spring.schemas</resource>
                            </transformer>
                            <transformer
                                    implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/>
                            <transformer
                                    implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                <mainClass>${start-class}</mainClass>
                            </transformer>
                        </transformers>
                    </configuration>
                </execution>
            </executions>
        </plugin>

Answer 2

I encountered this issue with version 2.3 of maven shade plugin when building a 2.6.x Spring boot jar. I removed the explicit version declaration in the maven shade plugin config and the issue was avoided. So likely I was originally using an incompatible maven shade version (2.3)