diff --git a/dodona-java.dockerfile b/dodona-java.dockerfile
index c463037..367e644 100644
--- a/dodona-java.dockerfile
+++ b/dodona-java.dockerfile
@@ -1,14 +1,21 @@
-FROM openjdk:8
+FROM amazoncorretto:8-alpine-jdk
 
 # Install jq for json querying in bash
-RUN apt-get update \
- && apt-get install -y --no-install-recommends jshon=20131010-3+b1 \
- && rm -rf /var/lib/apt/lists/* \
- # Make sure the students can't find our secret path, which is mounted in
- # /mnt with a secure random name.
- && chmod 711 /mnt \
- # Add the user which will run the student's code and the judge.
- && useradd -m runner
+RUN <<EOF
+  set -eux
+
+  apk add --no-cache jq
+
+
+  # Make sure the students can't find our secret path, which is mounted in
+  # /mnt with a secure random name.
+  chmod 711 /mnt
+
+  # Add the user which will run the student's code and the judge.
+  adduser -u 1000 -S runner
+  rm -rf /var/cache/apk/*
+
+EOF
 
 # As the runner user
 USER runner