Comparing Disassembled Java Class From JVM Languages

All JVM languages come with some degrees of syntactic sugar to make the code easier to read and write.

To satisfy my curiosity, I decided to run javap command to disassemble the bytecode inside the class file generated from several JVM languages. The chosen languages are Java, Groovy, Scala, JRuby and Rhino. I left out Clojure because the syntax does not compute for me after having my heavy lunch.

JAVA

Source Code

public class JavaPerson {
    private String name;
    private int age;

    public JavaPerson(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }
}

Disassembled Java Class

public class com.choonchernlim.epicapp.JavaPerson {
  public com.choonchernlim.epicapp.JavaPerson(java.lang.String, int);
  public java.lang.String getName();
  public int getAge();
}

GROOVY

Source Code

class GroovyPerson {
    String name
    int age
}

Disassembled Java Class

public class com.choonchernlim.epicapp.GroovyPerson implements groovy.lang.GroovyObject {
  public static transient boolean __$stMC;
  public static long __timeStamp;
  public static long __timeStamp__239_neverHappen1395328777863;
  public com.choonchernlim.epicapp.GroovyPerson();
  public java.lang.Object this$dist$invoke$1(java.lang.String, java.lang.Object);
  public void this$dist$set$1(java.lang.String, java.lang.Object);
  public java.lang.Object this$dist$get$1(java.lang.String);
  protected groovy.lang.MetaClass $getStaticMetaClass();
  public groovy.lang.MetaClass getMetaClass();
  public void setMetaClass(groovy.lang.MetaClass);
  public java.lang.Object invokeMethod(java.lang.String, java.lang.Object);
  public java.lang.Object getProperty(java.lang.String);
  public void setProperty(java.lang.String, java.lang.Object);
  public static void __$swapInit();
  static {};
  public java.lang.String getName();
  public void setName(java.lang.String);
  public int getAge();
  public void setAge(int);
  public void super$1$wait();
  public java.lang.String super$1$toString();
  public void super$1$wait(long);
  public void super$1$wait(long, int);
  public void super$1$notify();
  public void super$1$notifyAll();
  public java.lang.Class super$1$getClass();
  public java.lang.Object super$1$clone();
  public boolean super$1$equals(java.lang.Object);
  public int super$1$hashCode();
  public void super$1$finalize();
  static java.lang.Class class$(java.lang.String);
}

SCALA

Source Code

class ScalaPerson(val name: String, val age: Int) {
}

Disassembled Java Class

public class ScalaPerson {
  public java.lang.String name();
  public int age();
  public ScalaPerson(java.lang.String, int);
}

JRUBY

Source Code

require 'java'

class JRubyPerson
  java_signature 'JRubyPerson(String, int)'
  def initialize (name, age)
    @name= name
    @age = age
  end

  java_signature 'String getName()'
  def name;
      @name
  end

  java_signature 'int getAge()'
  def age;
    @age
  end
end

Disassembled Java Class

public class JRubyPerson extends org.jruby.RubyObject {
  public static org.jruby.runtime.builtin.IRubyObject __allocate__(org.jruby.Ruby, org.jruby.RubyClass);
  public JRubyPerson(java.lang.String, int);
  public java.lang.String getName();
  public int getAge();
  static {};
}

RHINO

Source Code

function RhinoPerson( name, age ) {
    this.name = name;
    this.age = age;

    this.getName = function () {
        return this.name;
    };

    this.getAge = function () {
        return this.age;
    };
}

Disassembled Java Class

public class RhinoPerson extends org.mozilla.javascript.NativeFunction implements org.mozilla.javascript.Script {
  public RhinoPerson(org.mozilla.javascript.Scriptable, org.mozilla.javascript.Context, int);
  public RhinoPerson();
  public static void main(java.lang.String[]);
  public final java.lang.Object exec(org.mozilla.javascript.Context, org.mozilla.javascript.Scriptable);
  public final java.lang.Object call(org.mozilla.javascript.Context, org.mozilla.javascript.Scriptable, org.mozilla.javascript.Scriptable, java.lang.Object[]);
  public int getLanguageVersion();
  public java.lang.String getFunctionName();
  public int getParamCount();
  public int getParamAndVarCount();
  public java.lang.String getParamOrVarName(int);
  public java.lang.String getEncodedSource();
  public boolean getParamOrVarConst(int);
}

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