You can build the project from sources available on GitHub.
sdk use java 11.0.16.1-zulu
mvn clean install
[INFO] Executed tasks
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary for Pi4J :: Parent POM 2.0-SNAPSHOT:
[INFO]
[INFO] Pi4J :: Parent POM ................................. SUCCESS [ 0.972 s]
[INFO] Pi4J :: DOCKER :: Docker Parent POM .............. SUCCESS [ 0.290 s]
[INFO] Pi4J :: TESTING :: Arduino Test Harness ........... SUCCESS [ 1.832 s]
[INFO] Pi4J :: LIBRARY :: Libraries Parent POM ........... SUCCESS [ 0.064 s]
[INFO] Pi4J :: LIBRARY :: JNI Wrapper for PIGPIO Library . SUCCESS [ 6.615 s]
[INFO] Pi4J :: LIBRARY :: Java Library (CORE) ............ SUCCESS [ 6.260 s]
[INFO] Pi4J :: PLUGIN :: Plugins Parent POM ............. SUCCESS [ 0.061 s]
[INFO] Pi4J :: PLUGIN :: Mock Platform & Providers ...... SUCCESS [ 0.683 s]
[INFO] Pi4J :: PLUGIN :: PIGPIO I/O Providers ........... SUCCESS [ 2.084 s]
[INFO] Pi4J :: PLUGIN :: RaspberryPi Platform & Providers SUCCESS [ 0.447 s]
[INFO] Pi4J :: TESTING :: Unit/Integration Tests ......... SUCCESS [ 2.350 s]
[INFO] Pi4J :: EXAMPLE :: Sample Code .................... SUCCESS [ 0.632 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
sdk use java 11.0.16.1-zulu
mvn clean install
/target/distribution/pi4j-core-2.0-SNAPSHOT.jar
/target/distribution/pi4j-demo-telegraph-1.0-SNAPSHOT.jar
/target/distribution/pi4j-library-pigpio-2.0-SNAPSHOT.jar
/target/distribution/pi4j-plugin-pigpio-2.0-SNAPSHOT.jar
/target/distribution/pi4j-plugin-raspberrypi-2.0-SNAPSHOT.jar
/target/distribution/run.sh
/target/distribution/slf4j-api-2.0.0-alpha0.jar
/target/distribution/slf4j-simple-2.0.0-alpha0.jar
./run.sh