Beyond JVM - YOW Melbourne 2013

Beyond JVM
A tour of upcoming technologies

Reminders
• Green/yellow/red rating system after talk

• Extended Q/A by blue chairs at 12:15

• If not green…stop by and tell me why

Me
• Charles Oliver Nutter

• Red Hat (yes, I have one; no, I don’t wear it)

• JRuby and JVM languages

• JVM hacking and spelunking

• @headius

Goals
• Get you excited about the future of JVM

• Show you there are very few unsolvables

• Convince you to get involved

What is “JVM”?
• The JVM is software that runs JVM bytecode

• Java, Scala, Groovy, JRuby, Clojure, …

• OpenJDK contains Sun’s JVM “HotSpot”

• Oracle’s JDK is based on OpenJDK

• Many other JVMs exist for many platforms

• Some just replace HotSpot

OSS JVMs
•
•
•
•
•
•
•
•
•

Avian

Azul Zulu

CACAO

Dalvik

GCJ

HaikuVM

HotSpot

•
•
•
•
•
•
•

IcedTea

IKVM.NET

•

Jamiga

JamVM

Jaos

Jato VM

Jelatine JVM

JESSICA

Jikes RVM
(Jikes Research
Virtual
Machine)

JOP

•
•
•
•
•
•
•
•
•

Juice

Jupiter

JwiK

Kaffe

leDos

MateVM

Maxine

Mika VM

miniMV

•
•
•
•
•

Mysaifu

•
•
•
•

SuperWaba

NanoVM

RoboVM

SableVM

Squawk virtual
machine

TakaTuka

TinyVM.

VM02

OpenJDK Timeline
• For years, Sun’s JDK is closed source

• Sun Microsystems starts OSS process in 2005

• Ofﬁcial announcement at JavaOne 2006

• HotSpot OSSed 12 Nov 2006

• JDK OSSed 8 May 2007

A 2006 report prepared for the EU
by UNU-MERIT stated that Sun was
the largest corporate contributor to
open source movements in the
world.

According to this report, Sun's open
source contributions exceed the
combined total of the next ﬁve
largest commercial contributors.

Sun Becomes Oracle
• Sun broke open the OSS piñata

• Java, Solaris, OpenOfﬁce, NetBeans,
VirtualBox, ZFS, Dtrace, and more

• Unable to capitalize on OSS

• Hardware can’t make up the difference

• Oracle takes over Sun…oh no!!!

Java SE 7 Updates
Time since last release

New numbering
90

Flurry of exploits
67.5

45

22.5

9mo of security releases
0

45

7u

40

7u

25

7u

21

7u

17

7u

15

7u

13

7u

11

7u

10

7u

9

7u

7

7u

6

7u

5

7u

4

7u

3

7u

2

7u

1

7u

The OpenJDK landscape looks different
this year. Oracle's complete grip on
OpenJDK is slowly loosening. They're
still the dominant player and perhaps
always will be, but things are more level
than they were.!
!

- Andrew Haley of Red Hat!
!

Upon nomination to the OpenJDK
governing board for 2013

Truths of OpenJDK
• It is really truly OSS, under GPL+CPE

• You can fork it

• You can distribute builds of it

• You can contribute to it

• Oracle is learning how to do OSS

Java 5 was released

September 30, 2004

Java 6 was released

December 11, 2006

Java 7 was released

July 28, 2011

Java 7 Features
• Strings in switch statements

• More numeric literal forms

• Type inference for generic instances

• try-with-resources statement

• Multiple-catch

static String chooseGreeting(String language) {"
        switch (language) {"
            case "Java": return "I love to hate you!";"
            case "Scala": return "I love you, I think!";"
            case "Clojure": return "(love I you)";"
            case "Groovy": return "I love ?: you";"
            case "Ruby": return "I.love? you # => true";"
            default: return "Who are you?";"
        }"
    }

Java 8 Features
• Lambda expressions

• Type annotations

Java 8 Features

•

Lambda expressions

• Type annotations

public static void doSort(List<String> input) {"
Collections.sort(input,!
(a,b)->Integer.compare(a.length(), b.length()));"
}"
"
public static String getInitials(List<String> input) {"
return input.stream()"
.map(x->x.substring(0,1))"
.collect(Collectors.joining());"
}

Java 9 Features?
• Modularization?

• Dynamic invocation?

• Value types?

• Reiﬁed generics?

• Coroutines? (working patch available!)

• Tail calls? (working patch available!)

High-Proﬁle Languages
• Clojure

• Groovy

• Scala

• JRuby

Newcomers
• Kotlin

• Ceylon

• Xtend

• Mirah

Classics
• Jython

• Rhino

• BeanShell

Ported Languages
•
•
•
•
•
•
•
•
•

Ada

AWK

BASIC

BBx

Boo

C

COBOL

ColdFusion

Railo

•

Open
BlueDragon

•

Common
Lisp

•

Component
Pascal

•
•
•
•

Erlang

Forth

Go

Haxe

•
•
•
•
•
•
•
•
•

JavaScript

Logo

Lua

Yeti ML

Oberon-2

OCaml

Object Pascal

PHP

Prolog

•
•
•
•
•
•
•

Python

R

REXX

Ruby

Scheme

Smalltalk

Tcl

New Languages
•
•
•
•
•
•
•
•
•
•
•

Alef++

Ateji PX

BBj

BeanShell

Ceylon

CAL

E

Fantom

Flow Java.

Fortress

Frege

•
•
•
•
•
•
•
•
•
•
•

Frink

Golo

Gosu

Hecl

Ioke

KBML

Kotlin

Jabaco

Jaskell

Jelly

Join Java

•
•
•
•
•
•
•
•
•
•
•

Joy

Judoscript

Libretto.

Mirah

N.A.M.E. Basic.

NetLogo

Nice

Noop

ObjectScript

PHP.reboot

Pizza

•
•
•
•
•
•
•
•

Pnuts

Processing

Stab

Sleep

V

X10

Xtend

Zest

User Code

Java

JNI call

C/native

JNI impl
Target Library

JNI
public class GetPidJNI {"
public static native long getpid();"
"
public static void main( String[] args ) {"
getpid();"
}"
"
static {"
System.load(!
System.getProperty("user.dir") +!
"/getpidjni.dylib");"
}"
}

JNI
/* DO NOT EDIT THIS FILE - it is machine generated */"
#include <jni.h>"
/* Header for class com_headius_jnr_presentation_GetPidJNI */"
"
#ifndef _Included_com_headius_jnr_presentation_GetPidJNI"
#define _Included_com_headius_jnr_presentation_GetPidJNI"
#ifdef __cplusplus"
extern "C" {"
#endif"
/*"
* Class:
com_headius_jnr_presentation_GetPidJNI"
* Method:
getpid"
* Signature: ()J"
*/"
JNIEXPORT jlong JNICALL Java_com_headius_jnr_1presentation_GetPidJNI_getpid"
(JNIEnv *, jclass);"
"
#ifdef __cplusplus"
}"
#endif"
#endif

JNI
#include "com_headius_jnr_presentation_GetPidJNI.h""
"
jlong JNICALL Java_com_headius_jnr_1presentation_GetPidJNI_getpid"
(JNIEnv *env, jclass c) {"
"
return getpid();"
}

JNI
$ gcc -I $JAVA_HOME/include -I
$JAVA_HOME/include/darwin -L
$JAVA_HOME/jre/lib/ -dynamiclib -ljava
-o getpidjni.dylib
com_headius_jnr_presentation_GetPidJNI.
c"
!

$ java -Djava.library.path=`pwd` -cp
target/jnr_presentation-1.0SNAPSHOT.jar
com.headius.jnr_presentation.GetPidJNI

Nobody enjoys calling
native libraries...

...but if you have to call
native libraries, you
might as well enjoy it.

Java Native Runtime
• Java API

• for calling Native code

• supported by a rich Runtime library

• You may be familiar with JNA

• Foreign Function Interface (FFI)

• https://github.com/jnr

• Maven artifacts for everything

A Java API for binding
native libraries and
native memory

Justiﬁcations
• NIO, NIO.2

• Native IO, symlinks, FS-walking,

• Unmanaged memory

• Selectable stdio, process IO

• Low-level or other sockets (UNIX, ICMP, ...)

• New APIs (graphics, crypto, OS, ...)

User Code
JNR stub

Java

JNI call

C/native

JNI impl
libfﬁ
Target Library

JNR
import jnr.ffi.LibraryLoader;"
import jnr.ffi.annotations.IgnoreError;"
"
public class GetPidJNRExample {"
public interface GetPid {"
long getpid();"
}"
"
GetPid getpid = LibraryLoader"
.create(GetPid.class)!
.load("c");"
"
getpid.getpid();"
}"
}

Layered Runtime
etc etc
jnr-posix

jnr-unixsocket!
jnr-enxio

jnr-constants

jnr-ffi
jffi
libffi

jnr-x86asm

JNR Platforms
• Darwin (OS X): universal (+ppc?)

• Linux: i386, x86_64, arm, ppc, ppc64, s390x

• Windows: i386, x86_64

• FreeBSD, OpenBSD: i386, x86_64

• SunOS: i386, x86_64, sparc, sparcv9

• AIX: ppc

• OpenVMS, AS/400: builds out there somewhere

• If your platform isn't here, contribute a build

jnr-fﬁ
• User-oriented API

• Roughly equivalent to what JNA gives you

• Functions, structs, callbacks, memory

• https://github.com/jnr/jnr-fﬁ

jnr-fﬁ
"
long getpid();"
}"
"
.load("c");"
"
getpid.getpid();"
}"
}

jnr-posix
• Pre-bound set of POSIX functions

• Mostly driven by what JRuby, Jython use

• Goal: 100% of POSIX bound to Java

public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
List<?

int chmod(String string, int i);"
int chown(String string, int i, int i1);"
int execv(String string, String[] strings);"
int execve(String string, String[] strings, String[] strings1);"
int fork();"
int seteuid(int i);"
int getgid();"
String getlogin();"
int getpgid();"
int getpgid(int i);"
int getpgrp();"
int getpid();"
int getppid();"
Passwd getpwent();!
Passwd getpwuid(int i);!
Passwd getpwnam(String string);"
Group getgrgid(int i);!
Group getgrnam(String string);"
int getuid();!
boolean isatty(FileDescriptor fd);"
int kill(int i, int i1);!
int symlink(String string, String string1);"
int link(String string, String string1);"
String readlink(String string) throws IOException;"
String getenv(String string);"
int setenv(String string, String string1, int i);"
int unsetenv(String string);"
int getpriority(int i, int i1);"
int setpriority(int i, int i1, int i2);"
int setuid(int i);"
FileStat stat(String string);"
int stat(String string, FileStat fs);"
int umask(int i);"
Times times();"
int utimes(String string, long[] longs, long[] longs1);"
int waitpid(int i, int[] ints, int i1);"
int wait(int[] ints);"
int errno();"
void errno(int i);"
int posix_spawnp(String string, List<? extends SpawnFileAction> list,
extends CharSequence> list1, List<? extends CharSequence> list2);

POSIX posix = POSIXFactory.getPOSIX(!
new MyPOSIXHandler(this),"
isNativeEnabled);

public interface POSIXHandler {!
public void error(Errno errno, String string);"
public void unimplementedError(String string);!
public void warn(WARNING_ID wrngd, String string, Object[] os);"
public boolean isVerbose();!
public File getCurrentWorkingDirectory();!
public String[] getEnv();!
public InputStream getInputStream();!
public PrintStream getOutputStream();!
public int getPID();!
public PrintStream getErrorStream();"
}

jnr-enxio
• Extended Native X-platform IO

• NIO-compatible JNR-backed IO library

• Read, write, select (kqueue, epoll, etc)

• Low-level fcntl control

• https://github.com/jnr/jnr-enxio

public class NativeSocketChannel"
extends AbstractSelectableChannel"
implements ByteChannel, NativeSelectableChannel {"
public NativeSocketChannel(int fd);!
public NativeSocketChannel(int fd, int ops);!
public final int validOps();!
public final int getFD();!
public int read(ByteBuffer dst) throws IOException;"
public int write(ByteBuffer src) throws IOException"
public void shutdownInput() throws IOException;"
public void shutdownOutput() throws IOException;!
}

jnr-unixsocket
• UNIX sockets for NIO

• Built atop jnr-enxio

• Fully selectable, etc

• https://github.com/jnr/jnr-unixsocket

JNA getpid

JNR getpid

getpid calls, 100M times
100000ms
10000ms
1000ms
100ms
10ms
1ms

@IgnoreError
"
@IgnoreError"
long getpid();"
}"
"
.load("c");"
"
getpid.getpid();"
}"
}

JNR getpid

JNR getpid @IgnoreError

2000ms

1500ms

1000ms

500ms

0ms

But There's More to Do
JNR getpid

JNI

JNR @IgnoreError

2000ms
1500ms
1000ms
500ms
0ms

GCC -O3

JVM Help is Coming
• Standard FFI API in JDK

• JIT intelligence

• Drop JNI overhead where possible

• Bind native call directly at call site

• Security policies, segv protection, etc

• Time for an FFI JSR

Recap
• OpenJDK is awesome

• Java is evolving

• JVM languages are everywhere

• Even native code is accessible

History
• JVM authors mentioned non-Java languages

• Language authors have targeted JVM

• Hundreds of JVM languages now

• But JVM was a mismatch for many of them

• Usually required tricks that defeated JVM
optimizations

• Or required features JDK could not provide

JVM
Opcodes
Invocation

Field Access

invokevirtual"
invokeinterface"
invokestatic"
invokespecial

getfield"
setfield"
getstatic"
setstatic

Stack

Flow Control

Boolean and Numeric

Array Access

*aload"
*astore"
b,s,c,i,l,d,f,a

Local Vars

Allocation

Goals of JSR 292
• A user-definable bytecode

• Full freedom to define VM behavior

• Fast method pointers + adapters

• Optimizable like normal Java code

• Avoid future modifications

A User-definable
Bytecode
You decide how the JVM implements it

+
Method Pointers
and Adapters
Faster than reflection, with user-defined

argument, flow, and exception handling

invokedynamic opcode
user-def’d bytecode

method pointers
MethodHandles

invokedynamic

Method Invocation
VM Operations

Method Lookup

Type Checking

Branch

Method Cache

obj.foo()

Target

Object
JVM

Call Site

instanceof

Object’s

Class
void foo()

void foo()
static void bar()

// Static"
System.currentTimeMillis()"
Math.log(1.0)"
"
// Virtual"
"hello".toUpperCase()"
System.out.println()"
"
// Interface"
myList.add("happy happy")"
myRunnable.run()"
"
// Special"
new ArrayList()"
super.equals(other)

// Static"
invokestatic java/lang/System.currentTimeMillis:()J"
invokestatic java/lang/Math.log:(D)D"
!
// Virtual"
invokevirtual java/lang/String.toUpperCase:()Ljava/lang/String;"
invokevirtual java/io/PrintStream.println:()V"
!
// Interface"
invokeinterface java/util/List.add:(Ljava/lang/Object;)Z"
invokeinterface java/lang/Runnable.add:()V"
!
// Special"
invokespecial java/util/ArrayList.<init>:()V"
invokespecial java/lang/Object.equals:(java/lang/Object)Z

invokevirtual"
1. Confirm object is of correct type

2. Confirm arguments are of correct type

3. Look up method on Java class

invokestatic
4. Cache method

5. Invoke method

invokestatic"


3. Cache method

4. Invoke method

invokevirtual
invokeinterface"
1. Confirm object’s type implements interface



invokeinterface
4. Cache method

5. Invoke method

invokespecial"
1. Confirm object is of correct type


3. Confirm target method is visible


5. Cache method

6. Invoke method

invokespecial
invokedynamic!
1. Call bootstrap handle (your code)

2. Bootstrap prepares CallSite + MethodHandle

3. MethodHandle invoked now and future (until CallSite changes)

invokedynamic bytecode
target method

bo
ot
st

ra
p

m

et
ho
d

method handles

Indy Languages
• New language impls

• JavaScript: Dyn.js and Nashorn

• Redline Smalltalk

• Improved language performance

• JRuby, Groovy, Jython

• Java features too!

JRuby/Java 6

JRuby/Java 7

Times Faster than Ruby 1.9.3
5
4.32

3.75

3.66
3.44

2.5

2.658

1.914

1.25

0

1.346

base64

1.565

1.538

richards

neural

redblack

red/black tree, pure Ruby versus native

ruby-2.0.0 + Ruby

2.48s

ruby-2.0.0 + C ext

0.51s

jruby + Ruby

0.29s

0

0.75

1.5
Runtime per iteration

2.25

3

Caveat Emptor
• Indy was really slow in ﬁrst Java 7 release

• Got fast in 7u2...and turned out broken

• Rewritten for 7u40

• Slow to warm up

• Still some issues (memory use, etc)

• Java 8 due in March…

JVM
Language

JVM
Bytecode

Out of our control

Written in C++

Bytecode
Interpreter

Bytecode
JIT

Native
Code

What If…
• The JVM’s JIT optimizer were written in Java

• You could customize how the JIT works for
your language or library

• JITed code could directly make native calls

Graal
• A 100% Java-based JIT framework

• Grew out of the 100% Java “Maxine” JVM

• Backends to assembly or HotSpot IR

• Directly control code generation

• Build a language without using JVM bytecode

• http://openjdk.java.net/projects/graal/

JVM
Language
Plain Java APIs

Graal

Intermediate
Representation

Graal
Optimizer

Under your control

Your
Transformations

Your
Optimizations

Native
Code

However…
• Not everyone is a compiler writer

• Graal’s IR is low-level and nontrivial

• Need to understand JVM internals

• Need some understanding of CPU

The Dream
• Design your language

• ???

• PROFIT

Without JVM

• Work out memory model

• Create an optimizing compiler

• Spend ten years debugging it

• PROFIT

With JVM

• Maybe write an interpreter

• Compile to JVM bytecode

• Pray that the JVM optimizes it right

• PROFIT

What We Want

• ???

• PROFIT

What We Want

• Write an interpreter

• PROFIT

Truffle
• Language framework built on Graal

• Designed to fulfill the dream

• Implement interpreter

• Truffle feeds that to backend

• No compiler expertise needed

• https://wiki.openjdk.java.net/display/Graal/Truffle+FAQ+and+Guidelines

Traditional Approach
Guest Language
AST interpreter in pure Java

Custom made bytecode compiler
Bytecode emitted by guest language

Any JVM

Truffle Atop JVM
Guest Language

Truffle
Bytecode based on interpreter flow

Any JVM

Trufﬂe Atop Graal
Guest Language

Trufﬂe
Direct access to compiler internals,

IR, machine code cache,

on stack replacement, etc etc

Graal JVM

The Final Word
• JVM is a powerful platform

• Java and other languages are evolving

• The JVM is adapting to our needs

• New tools breaking JVM’s boundaries

Thank you!
• Charles Oliver Nutter

• @headius, headius@headius.com

• http://blog.headius.com

Beyond JVM - YOW Melbourne 2013

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