Fixes to ensure CodeQL can work with Java projects (#13)

* Fixes to ensure CodeQL can work with Java projects

* Removed debug noise from Dockerfile

Dockerfile

@@ -35,12 +35,12 @@ RUN apt-get update && \
         ln -s /usr/bin/python3.8 /usr/bin/python && \
         ln -s /usr/bin/pip3 /usr/bin/pip 
 
-# Install .NET Core for tools/builds
+# Install .NET Core and Java for tools/builds
 RUN cd /tmp && \
     wget https://packages.microsoft.com/config/ubuntu/20.04/packages-microsoft-prod.deb -O packages-microsoft-prod.deb && \
     dpkg -i packages-microsoft-prod.deb && \
     apt-get update; \
-    apt-get install -y apt-transport-https && \
+    apt-get install -y default-jdk apt-transport-https && \
     apt-get update && \
     rm packages-microsoft-prod.deb
 RUN apt-get install -y dotnet-sdk-3.1