"Unable to run a simple JNI program" error message when installing rJava on R 3.6 for ubuntu bionic beaver

I have the very common problem that rJava does not install correctly on Ubuntu. This problem has been dsicussed in multiple places here, here, here, to name a few.

The basic problem is that on installing the rJava package, the following error message is produced

configure: error: Unable to run a simple JNI program. Make sure you have configured R with Java support (see R documentation) and check config.log for failure reason.
Warning in system(cmd) : error in running command
ERROR: configuration failed for package ‘rJava’
* removing ‘/home/jonno/R/x86_64-pc-linux-gnu-library/3.6/rJava’

There are various closely related solutions to this problem. Most of them use sudo R CMD javareconf to configure Java for R (also a -e variant). Some suggest setting the JAVA_HOME path in the environment variables (others say not to). Others suggest uninstalling and re-installing R whilst others suggest installing rJava from cran. There are several who reccomend update alternatives. There are other variants of these solutions.

I have tried combinations of all of the above, and have got nowhere, so am clearly doing something wrong.

entering echo $JAVA_HOME returns

/usr/lib/jvm/java-11-openjdk-amd64

my etc/environment looks like this

PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/$
MKL_THREADING_LAYER=GNU
JAVA_HOME="/usr/lib/jvm/java-11-openjdk-amd64"

When I run R CMD javaconf, it looks like this

Java interpreter : /usr/lib/jvm/java-11-openjdk-amd64/java
Java version     : 11.0.4
Java home path   : /usr/lib/jvm/java-11-openjdk-amd64
Java compiler    : /usr/lib/jvm/java-11-openjdk-amd64/bin/javac
Java headers gen.: /usr/bin/javah
Java archive tool: /usr/lib/jvm/java-11-openjdk-amd64/bin/jar

trying to compile and link a JNI program 
detected JNI cpp flags    : -I$(JAVA_HOME)/include -I$(JAVA_HOME)/include/linux
detected JNI linker flags : -L$(JAVA_HOME)/lib/server -ljvm
gcc -std=gnu99 -I"/usr/share/R/include" -DNDEBUG -I/usr/lib/jvm/java-11-openjdk-amd64/include -I/usr/lib/jvm/java-11-openjdk-amd64/include/linux    -fpic  -g -O2 -fdebug-prefix-map=/build/r-base-uuRxut/r-base-3.6.1=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -g  -c conftest.c -o conftest.o
gcc -std=gnu99 -shared -L/usr/lib/R/lib -Wl,-Bsymbolic-functions -Wl,-z,relro -o conftest.so conftest.o -L/usr/lib/jvm/java-11-openjdk-amd64/lib/server -ljvm -L/usr/lib/R/lib -lR


JAVA_HOME        : /usr/lib/jvm/java-11-openjdk-amd64
Java library path: $(JAVA_HOME)/lib/server
JNI cpp flags    : -I$(JAVA_HOME)/include -I$(JAVA_HOME)/include/linux
JNI linker flags : -L$(JAVA_HOME)/lib/server -ljvm
Updating Java configuration in /usr/lib/R
Done.

What am I doing wrong and how do I get rJava to install properly?