rJava JRI Error R is already initialized (R Call java(new Rengine in Java )) - rjava

Question

I could call R from Java and call Java function from R successfully both.
However, when I'm trying to use rJava JRI to call Java from R, and Java code instance new REngine. It failed reports
R is already initialized
and then quit R directly.
My class:
public class testRJava {
public void testOK(){
System.out.println("test this funciton could be called OK");
}
public void callSample(){
Rengine re = Rengine.getMainEngine();
if(re == null){
re=new Rengine (new String [] {"--vanilla"}, false, null);
if (!re.waitForR())
{
System.out.println ("Cannot load R");
return;
}
}
// print a random number from uniform distribution
System.out.println (re.eval ("runif(100)").asDouble());
re.end();
}
}
then, I call the Jar from R
> b <- .jnew("testRJava")
> b$testOK()
test this funciton could be called OK
> b$
b$callSample() b$main( b$wait() b$toString() b$getClass() b$notifyAll()
b$testOK() b$wait( b$equals( b$hashCode() b$notify()
> b$callSample()
R is already initialized
[root# home]#
Any one know why? Any solution about this error ?

Answer 1

library(rJava)
.jinit(".")
.jengine(TRUE)
[1] "Java-Object{Thread[Thread-0,5,main]}"
b <- .jnew("testRJava")
b$callSample()