Set the version in the POM file before building the package

Makefile

@@ -109,7 +109,7 @@ java:
 	mv java_bin/java java_bin/daff/src/main
 	cp packaging/java/pom.xml java_bin/daff
 	cp scripts/Example.java java_bin
-	cd java_bin/daff; mvn -Drevision=$(version) clean package
+	cd java_bin/daff; mvn build-helper:parse-version versions:set -DnewVersion=$(version) versions:commit; mvn clean package
 	cd java_bin; javac -cp daff/target/daff-$(version).jar Example.java
 	@echo 'Output in java_bin/daff/target, run "java -jar java_bin/daff/target/daff-$(version).jar" for help'
 	@echo 'Run example with "java -cp java_bin/daff/target/daff-$(version).jar:java_bin Example"'

RELEASE.md

@@ -3,12 +3,12 @@
 In order to publish `daff` to Maven Central, the file `~/.jreleaser/config.properties` with the following contents is required:
 
 ```bash
-JRELEASER_NEXUS2_USERNAME="<your-sonatype-account-username>"
-JRELEASER_NEXUS2_PASSWORD="<your-sonatype-account-password>"
-JRELEASER_GPG_PASSPHRASE="<your-pgp-passphrase>"
-JRELEASER_GPG_PUBLIC_KEY="/path/to/public.gpg"
-JRELEASER_GPG_SECRET_KEY="/path/to/private.gpg"
-JRELEASER_GITHUB_TOKEN="<your-github-token>"
+JRELEASER_NEXUS2_USERNAME=<your-sonatype-account-username>
+JRELEASER_NEXUS2_PASSWORD=<your-sonatype-account-password>
+JRELEASER_GPG_PASSPHRASE=<your-pgp-passphrase>
+JRELEASER_GPG_PUBLIC_KEY=/path/to/public.gpg
+JRELEASER_GPG_SECRET_KEY=/path/to/private.gpg
+JRELEASER_GITHUB_TOKEN=<your-github-token>
 ```
 
 In order to get a Sonatype account, follow [the steps in this guide](https://maciejwalkowiak.com/blog/guide-java-publish-to-maven-central/).
@@ -28,30 +28,22 @@ gpg --output private.gpg --armor --export-secret-key username@email-host
 
 The GitHub token can be generated in GitHub/User Profile/Settings/Developer settings.
 
-Once all configuration is in place, execute the following commands.
-
-In the repository root:
-
-```bash
-export version=$(grep "\"version\"" package.json | grep -E -o "[.0-9]+")
-```
-
- In the directory `java_bin/daff` (from JReleaser's [docs](https://jreleaser.org/guide/latest/examples/maven/maven-central.html)):
+Once all configuration is in place, execute the following commands from the directory `java_bin/daff` (from JReleaser's [docs](https://jreleaser.org/guide/latest/examples/maven/maven-central.html)):
 
 1) Verify release & deploy configuration
 
 ```bash
-mvn -Drevision=$version jreleaser:config
+mvn jreleaser:config
 ```
 
 2) Stage all artifacts to a local directory
 
 ```bash
-mvn -Drevision=$version -Ppublication
+mvn -Ppublication
 ```
 
 3) Deploy and release
 
 ```bash
-mvn -Drevision=$version jreleaser:full-release
+mvn jreleaser:full-release
 ```

packaging/java/pom.xml

@@ -4,7 +4,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>io.github.paulfitz</groupId>
     <artifactId>daff</artifactId>
-    <version>${revision}</version>
+    <version>0.0.0</version>
     <packaging>jar</packaging>
 
     <name>daff</name>
@@ -42,6 +42,11 @@
     <build>
         <pluginManagement>
             <plugins>
+                <plugin>
+                    <groupId>org.codehaus.mojo</groupId>
+                    <artifactId>build-helper-maven-plugin</artifactId>
+                    <version>3.4.0</version>
+                </plugin>
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-deploy-plugin</artifactId>