The REPL as a scripting engine

To deal with interoperability with programs written in scripting languages, the Java community process has defined JSR-223, Scripting for the JavaTM Platform, a Java specification request that makes it possible to execute scripts written in other languages (such as Groovy, JavaScript, Ruby, or Jython to name of few) from within a Java program. For instance, we can write a Java program embedding a basic JavaScript snippet as follows:

package com.demo;
import javax.script.*;

public class JSR223Sample { 

  public static void main(String[] args) throws Exception {
    ScriptEngineManager manager = new ScriptEngineManager();
    ScriptEngine engine = manager.getEngineByName("JavaScript");

    // expose object as variable to script
    engine.put("n", 5);

    // evaluate a script string. 
    engine.eval("for(i=1; i<= n; i++) println(i)");
  }
}

We will get the following output from the IDE:

run:
1
2
3
4
5
BUILD SUCCESSFUL (total time: 0 seconds)

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