如何在 MacOSX 上处理 R 代码中的 Java 错误？

Question

When running my R-code using Shiny I get the following error message, only on my Mac (Catalina, V 10.15.1) but not on Windows:

Unable to find any JVMs matching version "(null)".
No Java runtime present, try --request to install.
Warnung in system("/usr/libexec/java_home", intern = TRUE)
  Ausführung von Kommando '/usr/libexec/java_home' ergab Status 1
Fehler: package or namespace load failed for ‘xlsx’:
 .onLoad failed in loadNamespace() for 'rJava', details:
  call: dyn.load(file, DLLpath = DLLpath, ...)
  error: kann shared object '/Library/Frameworks/R.framework/Versions/3.6/Resources/library/rJava/libs/rJava.so' nicht laden:
  dlopen(/Library/Frameworks/R.framework/Versions/3.6/Resources/library/rJava/libs/rJava.so, 6): Library not loaded: /Library/Java/JavaVirtualMachines/jdk-11.0.1.jdk/Contents/Home/lib/server/libjvm.dylib
  Referenced from: /Library/Frameworks/R.framework/Versions/3.6/Resources/library/rJava/libs/rJava.so
  Reason: image not found

As my code is very extensive and long I cannot post it on here. However, I would appreciate any help as I am still a beginner. Thank you!

Answer 1

MacOS X does not come with Java Development Kits (JDKs) pre-installed.

I recommend installing via HomeBrew then run the command: brew cask install java and it will install the latest Oracle JDK and sort out any config for you.

Once you have the JDK, try running your R-Code again, it should be working fine and you should not see the Unable to find any JVMs error.