library(xlsx)
Loading required package: rJava
Error : .onLoad failed in loadNamespace() for 'rJava', details:
call: fun(libname, pkgname)
error: JAVA_HOME cannot be determined from the Registry
In addition: Warning messages:
1: package ‘xlsx’ was built under R version 3.2.5
2: package ‘rJava’ was built under R version 3.2.5
Error: package ‘rJava’ could not be loaded
Hi,
You could miss Java requirement on your system. see rJava
For xlsx reading and manipulation know that there is openxlsx and readxl and writexl; All of them does not have the java dependency.
One advice for next time: do not hesitate to provide some context and some friendly introduction too ! 
5 Likes