【求助】关于安装xlsx包遇到的疑点问题

错误代码如下
> library(xlsx)
WARNING: Initial Java 12 release has broken JNI support and does NOT work. Use stable Java 11 (or watch for 12u if avaiable).
ERROR: Java exception occurred during rJava bootstrap - see stderr for Java stack trace.
Exception in thread "main" java.lang.NoClassDefFoundError: java.lang.System
WARNING: Initial Java 12 release has broken JNI support and does NOT work. Use stable Java 11 (or watch for 12u if avaiable).
ERROR: Java exception occurred during rJava bootstrap - see stderr for Java stack trace.
Exception in thread "main" java.lang.NullPointerException
at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:291)
at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:281)
at java.base/java.lang.reflect.Method.checkCanSetAccessible(Method.java:198)
at java.base/java.lang.reflect.Method.setAccessible(Method.java:192)
Error: package or namespace load failed for ‘xlsx’:
loadNamespace()里算'xlsx'时.onLoad失败了，详细内容：
调用: .jcall("java.lang.System", "S", "getProperty", "java.version")
错误: RcallMethod: cannot determine object class