diff --git a/Dockerfile b/Dockerfile
index 84d60518bd822cb09d1be284a1d45de7dc3d086b..816b10cdfc29b452efed1de3ae2339e3375c2d41 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -18,10 +18,11 @@ RUN android-sdk-linux/tools/bin/sdkmanager \
 
 FROM ubuntu:focal
 COPY --from=builder /android-sdk-linux /android-sdk-linux
+RUN ln -s /android-sdk-linux/build-tools/${BUILD_TOOLS}/apksigner /usr/local/bin/apksigner
 
 RUN apt-get update && \
     DEBIAN_FRONTEND=noninteractive TZ=Etc/UTC apt-get -y install --no-install-recommends \
-    git python3-pip python3-wheel python3-setuptools python3-venv tzdata && \
+    default-jdk-headless git python3-pip python3-wheel python3-setuptools python3-venv tzdata && \
     apt-get install -y --no-install-recommends $(apt-cache depends fdroidserver | grep -Fv -e java -e jdk -e '<' | awk '/Depends:/{print$2}') && \
     rm -rf /var/lib/apt/lists/*