Using R Code in Java Eclipse with rJava

This post shows how to use R code in Eclipse IDE for Java with rJava package. But this work requires several environment setting which is a little bit confusing. Although there are some good posts regarding this issue, we use a step by step guide with detailed screen captures for clear understanding.


Occasionally we would encounter some problems which are not easy to implement in Java. Among them are financial or econometric model estimation or optimization, to name a few. But in many cases, these problems are easily solved in R thanks to its various packages which are supported by worldwide experts.

This leads to the necessity of the connection between R and Java. For this purpose, rJava package provides this interface functionality but environment setting is not easy.

With detailed screen captures, let’s find the efficient way to use rJava in Eclipse. For convenience, we assume R and Eclipse are installed already.

Installing rJava

We need to install rJava package in R studio.

We need to know the directory where rJava package is installed. In our case, this directory is as follow. (this is dependent on your Windows system)


The following figure displays files of rJava/jri directory.

Environment Variables

Find “Edit the system environment variables” and open System Properties box, and click Environment Variables … button.

Add Path as a new variable in System Variables as follows.

  • Path : C:\Users\shlee\Documents\R\win-library\4.0\rJava\jri\x64;

Eclipse Project and Class

Make a new project in Eclipse : File -> New -> Java Project .

Insert aRjava or your favorite name as Project name.

  • Project name : aRjava

Make a new class : File -> New -> Class .

Insert CRjava or your favorite name as Name.

  • Name : CRjava

Visit SH Fintech Modeling Blog for instructions on how to write a Java code with rJava and to read the full article.

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