[R] How do I use simple calls to java methods?

Jeff Newmiller jdnewmil at dcn.davis.CA.us
Tue Oct 22 16:38:31 CEST 2013

I don't use rJava, but numerous examples came up when I Googled for "rjava examples". The fact that you have not referenced any of that material may be leaving a bad taste in the mouths of those few people who do use both R and Java. Or, they may just not spend time wading through emails on this list.

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Hurr <hill0093 at umn.edu> wrote:
>I am surprised to not get a reply. 
>I suppose this means that extremely few, if any, use rJava.
>rJava.pdf says this, but I am too stupid to interpret it:
>.jcall calls a Java method with the supplied arguments.
>.jcall(obj, returnSig = "V", method, ..., evalArray = TRUE,
>evalString = TRUE, check = TRUE, interface = "RcallMethod",
>simplify = FALSE, use.true.class = FALSE)
>Perhaps it means that to replace:
>      calCk <- calStgOfLinTim(linTm,tlev) 
>and use something like:
>      calCk <- .jcall(CalqsLin.class,returnSig = "S",
>      calStgOfLinTim(linTm,tlev),evalArray=FALSE, 
>      evalString = TRUE, check = TRUE, interface = "RcallMethod",
>      simplify = FALSE, use.true.class = TRUE)
>I suppose there are other setup things to do, 
>like start the JVM (java Virtual machine)
>and I don't know what obj means.
>Anyway, if I am able to do these simple java method calls, 
>it will be a big plus to our data analysis lab to use R conveniently.
>Please help
>View this message in context:
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>R-help at r-project.org mailing list
>PLEASE do read the posting guide
>and provide commented, minimal, self-contained, reproducible code.

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