help with knowing what's the reason it's not installed

.buildkite/hooks/prepare-common.sh

@@ -5,19 +5,23 @@ set -euo pipefail
 JAVA_VERSION=$(cat .java-version | xargs | tr -dc '[:print:]')
 JAVA_HOME="${HOME}/.java/openjdk${JAVA_VERSION}"
 export JAVA_HOME
-PATH="${JAVA_HOME}/bin:$PATH"
+PATH="${JAVA_HOME}/bin:${PATH}"
 export PATH
 
-# Fallback to install at runtime
-if [ ! -d "${JAVA_HOME}" ] ; then
+if [ -d "${JAVA_HOME}" ] ; then
+  echo "--- Skip installing JDK${JAVA_VERSION} :java:"
+  echo "already available in the Buildkite runner"
+else
+  # Fallback to install at runtime
   # This should not be the case normally untless the .java-version file has been changed
   # and the VM Image is not yet available with the latest version.
   echo "--- Install JDK${JAVA_VERSION} :java:"
   JAVA_URL=https://jvm-catalog.elastic.co/jdk
   JAVA_PKG="${JAVA_URL}/latest_openjdk_${JAVA_VERSION}_linux.tar.gz"
-  curl -L --output /tmp/jdk.tar.gz "$JAVA_PKG"
-  mkdir -p "$JAVA_HOME"
-  tar --extract --file /tmp/jdk.tar.gz --directory "$JAVA_HOME" --strip-components 1
+  curl -L --output /tmp/jdk.tar.gz "${JAVA_PKG}"
+  mkdir -p "${JAVA_HOME}"
+  tar --extract --file /tmp/jdk.tar.gz --directory "${JAVA_HOME}" --strip-components 1
 fi
 
+# Validate java is available in the runner.
 java -version