build.sh

#!/usr/bin/env bash

echo "---> Java buildpack"

set -eo pipefail

env_dir=$1/env
cache_dir=$2

jdk_url="https://cdn.azul.com/zulu/bin/zulu8.28.0.1-jdk8.0.163-linux_x64.tar.gz"
jdk_version="1.8.0_163"

maven_url="https://apache.org/dist/maven/maven-3/3.5.4/binaries/apache-maven-3.5.4-bin.tar.gz"
maven_version="3.5.4"

# Load user-provided build-time environment variables
if compgen -G "$env_dir/*" > /dev/null; then
  for var in "$env_dir"/*; do
    declare "$(basename "$var")=$(<"$var")"
  done
fi

echo "---> Installing JDK"

rm -rf .jdk
mkdir -p .jdk
wget -q -O - "$jdk_url" | tar pxz -C .jdk --strip-components=1
export PATH=.jdk/bin:$PATH

mkdir -p .profile
cat << EOF > .profile/jdk.sh
export JAVA_HOME=$launch_dir/jdk
if [[ -z \$LD_LIBRARY_PATH ]]; then
  export LD_LIBRARY_PATH="\$JAVA_HOME/jre/lib/amd64/server"
else
  export LD_LIBRARY_PATH="\$JAVA_HOME/jre/lib/amd64/server:$LD_LIBRARY_PATH"
fi
EOF
fi

mkdir -p $cache_dir/maven_m2
ln -s $cache_dir/maven_m2 $HOME/.m2
MAVEN_OPTS="${MAVEN_OPTS:-"-XX:+UnlockExperimentalVMOptions -XX:+UseCGroupMemoryLimitForHeap"}"

echo "---> Running Maven Wrapper"
./mvnw clean install -B -DskipTests

# Set default start command
for jarFile in $(find target -maxdepth 1 -name "*.jar" -type f); do
  echo "processes = [{ type = \"web\", command = \"java -jar $jarFile\"}]" > "$launch_dir/launch.toml"
  break;
done