Problems when trying to load a package in R due to rJava

Solution 1:

The reason is probably linked to the fact you are using a 64-bit OS and R version but do not have Java installed with the same architecture. What you have to do is to download Java 64-bit from this page: https://www.java.com/en/download/manual.jsp

After that just try to reload the xlsx package. You shouldn't need to re-start R.

Solution 2:

Its because either one of the Java versions(32 bit/64 bit) is missing from your computer. Try installing both the Jdks and run the code.
After installing the Jdks open R and type the code

system("java -version")

This will give you the version of Jdk installed. Then try loading the rJava package. This worked for me.