A look at bytecode: let's see what code turns into

Trying to be "idiomatic" yet fair. Used JD GUI to show the bytecode in human-readable Java.

Somehow mirah breaks JD GUI, which is probably interesting.
So I went through an intermediate Java file thanks to mirah -j instead.

Bottles.groovy

import groovy.transform.CompileStatic

@CompileStatic
class Bottles {
    static void main(String... args) {
      for (n in 1..100)
        println "${n} bottles"
    }
}

Bottles.groovy.decompiled.java

import groovy.lang.GroovyObject;
import groovy.lang.IntRange;
import groovy.lang.MetaClass;
import groovy.transform.TypeChecked.TypeCheckingInfo;
import java.util.Iterator;
import org.codehaus.groovy.runtime.DefaultGroovyMethods;
import org.codehaus.groovy.runtime.GStringImpl;
import org.codehaus.groovy.runtime.ScriptBytecodeAdapter;

public class Bottles
  implements GroovyObject
{
  public Bottles()
  {
    Bottles this;
    MetaClass localMetaClass = $getStaticMetaClass();
    this.metaClass = localMetaClass;
  }

  @TypeChecked.TypeCheckingInfo(inferredType="AAlDbGFzc05vZGUAAAFWAP////8=", version=1)
  public static void main(String[] args)
  {
    Integer n = null; for (Iterator localIterator = ((IntRange)ScriptBytecodeAdapter.createRange(Integer.valueOf(1), Integer.valueOf(100), 1)).iterator(); localIterator.hasNext(); 
      null)
    {
      n = (Integer)ScriptBytecodeAdapter.castToType(localIterator.next(), Integer.class);
      DefaultGroovyMethods.println(Bottles.class, new GStringImpl(new Object[] { n }, new String[] { "", " bottles" }));
    }
  }

  static
  {
    __$swapInit();
    long l1 = 0L;
    __timeStamp__239_neverHappen1355612245284 = l1;
    long l2 = 1355612245284L;
  }
}

Bottles.java

class Bottles {
    public static final void main(String[] args) {
        for (int i = 1; i <= 100; i++)
            System.out.println(i + " bottles");
    }
}

Bottles.java.decompiled.java

import java.io.PrintStream;

class Bottles
{
  public static final void main(String[] paramArrayOfString)
  {
    for (int i = 1; i <= 100; i++)
      System.out.println(i + " bottles");
  }
}

Bottles.kt.decompiled.java

package Bottles;

import jet.runtime.typeinfo.JetMethod;
import jet.runtime.typeinfo.JetValueParameter;

public class namespace
{
  @JetMethod(flags=16, returnType="V")
  public static final void main(@JetValueParameter(name="args", type="[Ljava/lang/String;") String[] args)
  {
    int i = 1; for (int j = 100; i <= j; 
      i++)
    {
      int n = i;
      kotlin.io.namespace.println(n + " bottles");
    }
  }
}

Bottles.mirah

1.upto 100 do |n|
  puts "#{n} bottles"
end

Bottles.mirah.decompiled.java

import java.io.PrintStream;

public class Bottles
{
  public static void main(String[] paramArrayOfString)
  {
    int i = 0;
    int j = 0;
    int k = 0;
    i = 1;
    j = 100;

    while (i <= j) {
      k = i;

      PrintStream localPrintStream = System.out;
      localPrintStream.println("" + k + " bottles");

      i += 1;
    }
  }
}

Bottles.scala

object Bottles {
  def main(args: Array[String]) =
    for (n <- (1 to 100))
      println(s"$n bottles!")
}

Bottles.scala.decompiled.java

import scala.LowPriorityImplicits;
import scala.Predef.;
import scala.Serializable;
import scala.StringContext;
import scala.collection.immutable.Range;
import scala.runtime.AbstractFunction1.mcVI.sp;
import scala.runtime.BoxesRunTime;
import scala.runtime.RichInt.;

public final class Bottles$
{
  public static final  MODULE$;

  static
  {
    new ();
  }

  public void main(String[] args)
  {
    RichInt..MODULE$.to$extension0(Predef..MODULE$.intWrapper(1), 100).foreach$mVc$sp(new AbstractFunction1.mcVI.sp() { public static final long serialVersionUID = 0L;

      public final void apply(int n) { apply$mcVI$sp(n); } 
      public void apply$mcVI$sp(int v1) { Predef..MODULE$.println(new StringContext(Predef..MODULE$.wrapRefArray((Object[])new String[] { "", " bottles!" })).s(Predef..MODULE$.genericWrapArray(new Object[] { BoxesRunTime.boxToInteger(v1) }))); }

    });
  }

  private Bottles$()
  {
    MODULE$ = this;
  }
}