Java ScriptEngineManager create various ScriptEngine

import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;

public class Main {
  public static void main(String[] args) {
    // Get the script engine manager
    ScriptEngineManager manager = new ScriptEngineManager();

    // Try executing scripts in Nashorn, Groovy, Jython, and JRuby
    execute(manager, "JavaScript", "print('Hello JavaScript')");
    execute(manager, "Groovy", "println('Hello Groovy')");
    execute(manager, "jython", "print 'Hello Jython'");
    execute(manager, "jruby", "puts('Hello JRuby')");
  }/*from   w w w  .  j a v  a  2  s. co m*/

  public static void execute(ScriptEngineManager manager, String engineName, String script) {
    // Try getting the engine
    ScriptEngine engine = manager.getEngineByName(engineName);
    if (engine == null) {
      System.out.println(engineName + " is not available.");
      return;
    }

    // If we get here, it means we have the engine installed. So, run the script
    try {
      engine.eval(script);
    } catch (ScriptException e) {
      e.printStackTrace();
    }
  }
}