A basic Processing sketch -using the grafica plotting library- in Java with R integration using Renjin. This sketch calls R's runif() command to generate 100 random numbers, multiplies these by 10 and creates a line plot of the result.

Sketch1.java

import javax.script.*;

/* The Processing.core.PApplet jar is included in the Processing.org download.
 * Search Google for "Processing Eclipse" to find instructions on how to get this
 * dependency available in Eclipse.
 */
import processing.core.PApplet;

/* 'grafica' is a third-party library for Processing.org, see https://github.com/jagracar/grafica.
 * The easiest thing to do is to copy the Java src/grafica directrory into your own project.
 */
import grafica.*;

/* Download the (latest version of the) Renjin script engine from 
 * http://nexus.bedatadriven.com/content/groups/public/org/renjin/renjin-script-engine/
 * Use the "jar-with-dependencies" from this link.
 */
import org.renjin.sexp.*;

public class Sketch1 extends PApplet {

  // Processing setup method
  public void setup() {
    size(500, 350);
    background(150);
    // Prepare the points for the plot
    int nPoints = 100;

    GPointsArray points = new GPointsArray(nPoints);
    try {
      points = Random(nPoints);
    } catch (Exception e) {
      e.printStackTrace();
    }

    // Create a new plot and set its position on the screen
    GPlot plot = new GPlot(this);
    plot.setPos(25, 25);

    // Set the plot title and the axis labels
    plot.setPoints(points);
    plot.getXAxis().setAxisLabelText("x axis");
    plot.getYAxis().setAxisLabelText("y axis");
    plot.setTitleText("A very simple example");

    // Draw it!
    plot.defaultDraw();
  }

  GPointsArray Random(int nPoints) throws Exception {

    GPointsArray points = new GPointsArray(nPoints);

    // create a script engine manager
    ScriptEngineManager factory = new ScriptEngineManager();
    // create a Renjin engine
    ScriptEngine engine = factory.getEngineByName("Renjin");
    // evaluate R code from String
    DoubleVector res = (DoubleVector)engine.eval("runif(100)");

    for(int i = 0; i < nPoints; i++){
      points.add(i, (float)(10*res.getElementAsDouble(i)));
    }
    return points;
  }

  // Processing draw method
  /*public void draw() {

  }*/
}