Shing Wai Chan and Ed Burns present their vision for Servlet 4.0, which brings HTTP 2.0 to the Java EE platform

2. HTTP
2
Comes
to
Java
What
Servlet
4.0
Means
to
You
Ed
Burns
and
Shing
Wai
Chan
Java
EE
Specifica=on
Team
Oracle
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|

3. Safe
Harbor
Statement
The
following
is
intended
to
outline
our
general
product
direc=on.
It
is
intended
for
informa=on
purposes
only,
and
may
not
be
incorporated
into
any
contract.
It
is
not
a
commitment
to
deliver
any
material,
code,
or
func=onality,
and
should
not
be
relied
upon
in
making
purchasing
decisions.
The
development,
release,
and
=ming
of
any
features
or
func=onality
described
for
Oracle’s
products
remains
at
the
sole
discre=on
of
Oracle.
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
3

4. Our
Plan
for
Your
Time
Investment
Why
HTTP
2?
HTTP
2
Big
Features
How
Servlet
Might
Expose
These
Features
Java
SE
9
Support
for
HTTP
2
Summary
and
Current
Status
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
1
2
3
4
5
S
4

5. Our
Plan
for
Your
Time
Investment
Why
HTTP
2?
HTTP
2
Big
Features
How
Servlet
Might
Expose
These
Features
Java
SE
9
Support
for
HTTP
2
Summary
and
Current
Status
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
1
2
3
4
5
S
5

6. .
.
.
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
Why
HTTP
2?
A
Real
Life
Example
S
index.html
style1.css
style2.css
script1.js
.
.
.
script9.js
pic1.jpg
pic8.jpg
photo1.png
photo2.png
.
.
.

7. Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
Why
HTTP
2?
Problems
in
HTTP
1.1
• HTTP
Pipelining
• Head-­‐of-­‐Line
blocking
S
style1.css
style2.css
Client
Server
index.html
index.html
style1.css
style2.css
script1.js
script2.js
.
.
.
script1.js
script2.js
.
.
.

8. Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
Why
HTTP
2?
Problems
in
HTTP
1.1
• Inefficient
use
of
TCP
sockets
S
Client
Server
Client
Server
Client
Server
Client
Server
Client
Server
Client
Server

9. Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
Why
HTTP
2?
What
is
an
opEmizaEon?
• Much
of
what
we
do
in
web-­‐apps
is
a
hack
to
work
around
shortcomings
in
HTTP
1.1
– File
concatena=on
and
image
sprites
– Domain
sharding
– Inlined
assets
E
9

10. File
Concatena=on
and
Image
Sprites
TCP
Efficiency
Improves
with
Larger
Files
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
E
10

11. File
Concatena=on
and
Image
Sprites
TCP
Efficiency
Improves
with
Larger
Files
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
E
11
• Modern
web
page
now
consists
of
more
than
90
resources
fetched
from
15
dis=nct
hosts
• Solu=on:
– Just
work
around
it
by
shoving
more
than
one
logical
file
into
one
physical
file.
– Seminal
ar=cle:
A
List
Apart
hPp://alistapart.com/arEcle/sprites
– Useful
tool:
SpritePad
hPp://spritepad.wearekiss.com/

12. File
Concatena=on
and
Image
Sprites
TCP
Efficiency
Improves
with
Larger
Files
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
E
12
.ic-AerospaceAndDefense-wht-on-gray, .ic-AerospaceAndDefense-wht-on-red,
.ic-Airline-wht-on-gray, .ic-Airline-wht-on-red{
background: url(sprites.png) no-repeat;
}
.ic-AerospaceAndDefense-wht-on-gray{
background-position: 0 0;
width: 80px;
height: 80px;
}
.ic-AerospaceAndDefense-wht-on-red{
background-position: -81px 0;
width: 80px;
height: 80px;
}
.ic-Airline-wht-on-gray{
background-position: 0 -80px ;
width: 80px;
height: 80px;
}
.ic-Airline-wht-on-red{
background-position: -81px -79px ;
width: 80px;
height: 80px;
}

13. Domain
Sharding
Split
page
resources
across
several
hosts
to
work
around
browser
limits
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
13

14. Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
Inlined
Assets
Base64
Encoding
Will
Never
Die
• data
URLs
• <img
src="data:image/gif;base64,R0lGODlhEAAOALMAAOazToeHh0tLS/
7LZv/0jvb29t/f3//Ub/
/ge8WSLf/rhf/3kdbW1mxsbP//mf///
yH5BAAAAAAALAAAAAAQAA4…"
/>
E
14

15. Our
Plan
for
Your
Time
Investment
Why
HTTP
2?
HTTP
2
Big
Features
How
Servlet
Might
Expose
These
Features
Java
SE
9
Support
for
HTTP
2
Summary
and
Current
Status
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
1
2
3
4
5
E
15

16. • Request/Response
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
mul=plexing
• Binary
Framing
• Stream
Priori=za=on
• Server
Push
• Header
Compression
• Upgrade
from
HTTP
1.1
• ALPN
(or
NPN)
• 101
Switching
Protocols
16
HTTP/2
Big
Ticket
Feature
Review
E

17. HTTP/2
Request
Response
Mul=plexing
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
• Fully
bi-­‐direc=onal
• Enabled
by
defining
some
terms
– Connec&on
A
TCP
socket
– Stream
A
“channel”
within
a
connec=on
– Message
A
logical
message,
such
as
a
request
or
a
response
– Frame
The
smallest
unit
of
communica=on
in
HTTP/2.
17
Lets
you
do
more
things
with
a
single
TCP
connecEon
S

18. HTTP/2
Request
Response
Mul=plexing
Copyright
©
2014,
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and/or
its
affiliates.
All
rights
reserved.
|
18
ConnecEons,
Streams,
Messages,
Frames
S

19. HTTP/2
Request
Response
Mul=plexing
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
• Once
you
break
the
communica=on
down
into
frames,
you
can
interweave
the
logical
streams
over
a
single
TCP
connec=on.
• Yet
another
idea
from
the
1960s
is
new
again.
19
ConnecEons,
Streams,
Messages,
Frames
S

20. Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
HTTP/2
Binary
Framing
• Solves
Head-­‐Of-­‐Line
(HOL)
blocking
problem
• Type
field
can
be
DATA,
HEADERS,
PRIORITY,
RST_STREAM,
SETTINGS,
PUSH_PROMISE,
PING,
GOAWAY,
WINDOW_UPDATE,
CONTINUATION
20
Enabled
by
dumping
newline
delimited
ASCII
S
Length
(24)
Type
(8)
Flags
(8)
R Stream
IdenEfier
(31)
Frame
Payload
(0
…)

21. Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
HTTP/2
Binary
Framing
GET
/index.html
HTTP/1.1
Host:
example.com
Accept:
text/html
21
Example
1
S
HEADERS
+
END_STREAM
+
END_HEADERS
:method:
GET
:scheme:
htp
:path:
/index.html
:authority:
example.org
accept:
text/html

22. Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
HTTP/2
Binary
Framing
HTTP/1.1
200
OK
Content-­‐Length:
11
Content-­‐Type:
text/html
Hello
World
22
Example
2
S
HEADERS
-­‐
END_STREAM
+
END_HEADERS
:status:
200
content-­‐length:
11
content-­‐type:
text/html
DATA
+
END_STREAM
Hello
World

23. HTTP/2
Stream
Priori=za=on
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
• Stream
Dependency
in
HEADERS
Frame
• PRIORITY
frame
type
• An
addi=onal
40
bytes
– Stream
id
(31)
– Weight
(8):
[1,
256]
– Exclusive
bit
(1)
• Only
an
advice
23
S
A
B
C
4
12
A
B
D
C
4
16
12
exclusive
=
0
A
D
16
B
C
4
12
exclusive
=
1

24. Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
HTTP/2
Server
Push
• Eliminates
the
need
for
resource
inlining.
• Lets
the
server
populate
the
browser’s
cache
in
advance
of
the
browser
asking
for
the
resource
to
put
in
the
cache.
• No
corresponding
JavaScript
API,
but
can
be
combined
with
SSE
– Server
pushes
stuff
into
the
browser’s
cache.
– Server
uses
SSE
to
tell
the
browser
to
go
fetch
it
(but
we
know
it’s
already
in
the
browser’s
cache).
24
E

25. HTTP/2
Header
Compression
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
• Observa=on:
most
of
the
headers
are
the
same
in
a
given
stream
– Host:
Accept:
user-­‐agent:
etc.
• Why
send
them
every
=me?
• Have
the
server
and
the
client
keep
tables
of
headers,
then
just
send
references
and
updates
to
the
tables.
25
Known
as
HPACK
E

26. HTTP/2
Upgrade
from
HTTP
1.1
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
• Not
secure
– We
have
to
use
port
80
– Use
exis=ng
101
Switching
Protocols
from
HTTP
1.1
• Secure
– Next
Protocol
Nego=a=on
(NPN)
– Applica=on
Layer
Protocol
Nego=a=on
26
Secure
or
not-­‐secure?
E

27. Our
Plan
for
Your
Time
Investment
Why
HTTP
2?
HTTP
2
Big
Features
How
Servlet
Might
Expose
These
Features
Java
SE
9
Support
for
HTTP
2
Summary
and
Current
Status
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
1
2
3
4
5
E
27

28. Servlet
4.0
Big
Ticket
New
Features
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
• Exis=ng
API
is
designed
for
One
Request
==
One
Response.
• HTTP/2
destroys
this
assump=on.
• It
will
be
challenging
to
do
jus=ce
to
the
new
reality
of
One
Request
==
One
or
More
Responses.
• We
must
not
simply
bolt
the
“One
or
More
Responses”
concept
onto
some
convenient
part
of
the
exis=ng
API.
28
Challenges
in
Exposing
HTTP/2
Features
in
Servlet
API
S

29. Servlet
4.0
Big
Ticket
New
Features
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
• Request/Response
mul=plexing
• Binary
Framing
• Stream
Priori=za=on
• Server
Push
• Header
Compression
• Upgrade
from
HTTP
1.1
– ALPN
or
(NPN)
– 101
Switching
Protocols
29
HTTP/2
Features
PotenEally
Exposed
in
Servlet
API
S

30. Servlet
4.0
Big
Ticket
New
Features
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
• Add
method
HttpServletRequest
and
HttpServletResponse
– int
getStreamId()
30
HTTP/2
Features
PotenEally
Exposed
in
Servlet
API
S

31. Servlet
4.0
Big
Ticket
New
Features
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
• Add
a
new
class
Priority
– boolean
exclusive
– int
streamId
– int
weight
• Add
method
to
HttpServletRequest
– Priority
getPriority()
• Add
methods
to
HttpServletResponse
– Priority
getPriority()
– void
setPriority(Priority
p)
31
Stream
PrioriEzaEon
S

32. Servlet
4.0
Big
Ticket
New
Features
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
• Push
resource
to
client
for
a
given
url
and
headers
• May
add
callback
for
comple=on
or
error
of
a
push
• Not
at
all
a
replacement
for
WebSocket
• Really
useful
for
frameworks
that
build
on
Servlet,
such
as
JSF
32
Server
Push
E

33. synthetic GET /style.css
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
33
Servlet
4.0
Big
Ticket
New
Features
Server
Push
Browser
Server Thread A
servlet.service()
GET /index.html
Server
discovers
browser will
need style.css
and script.js
Server Thread B
servlet.service()
request.dispatchPushRequest("style.css")
request.dispatchPushRequest("script.js")
synthetic GET /script.js
Server Thread C
servlet.service()
style.css
script.js
index.html
E

34. Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
Server
Push
Example
of
PotenEal
Use
from
JSF
public
class
FacesServlet
implements
Servlet
{
public
void
service(ServletRequest
req,
ServletResponse
resp)
throws
IOException,
ServletException
{
//..
HttpServletRequest
request
=
(HttpServletRequest)
req;
try
{
ResourceHandler
handler
=
context.getApplication().getResourceHandler();
if
(handler.isResourceRequest(context)
||
request.isPushRequest())
{
handler.handleResourceRequest(context);
}
else
{
lifecycle.attachWindow(context);
lifecycle.execute(context);
lifecycle.render(context);
}
}
}
E
34

35. Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
Server
Push
Example
of
PotenEal
Use
from
JSF
public
class
ExternalContextImpl
extends
ExternalContext
{
//…
public
String
encodeResourceURL(String
url)
{
if
(null
==
url)
{
String
message
=
MessageUtils.getExceptionMessageString
(MessageUtils.NULL_PARAMETERS_ERROR_MESSAGE_ID,
"url");
throw
new
NullPointerException(message);
}
Map
attrs
=
getResourceAttrs();
((HttpServletRequest)
request).dispatchPushRequest(url,
attrs);
return
((HttpServletResponse)
response).encodeURL(url);
}
//…
}
E
35

36. Elas=c
Resilient
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
Reac=ve
Programming
36
S
Responsive
Message
Driven
image
credit:
reac=vemanifesto.org

37. Servlet
4.0
and
Reac=ve
Programming
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
• Non-­‐blocking
IO
in
Servlet
3.1
– ServletInputStream
• #setReadListener,
#isReady
– ServletOutputStream
• #setWriteListener,
#isReady
– ReadListener
• #onDataAvailable,
#onAllDataRead,
#onError
– WriteListener
• #onWritePossible,
#onError
S
37

38. Servlet
4.0
and
Reac=ve
Programming
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
• Asynchronous
in
Servlet
3.0
– ServletRequest#startAsync
– AsyncContext
• #addListener,
#dispatch,
#complete
– AsyncListener
• #onComplete,
#onError,
#onStartAsync,
#onTimeout
• Event-­‐driven
– Server-­‐Sent
Events
S
38

39. Our
Plan
for
Your
Time
Investment
Why
HTTP
2?
HTTP
2
Big
Features
How
Servlet
Might
Expose
These
Features
Java
SE
9
Support
for
HTTP
2
Summary
and
Current
Status
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
1
2
3
4
5
E
39

40. Java
SE
9
Support
for
HTTP/2
• JEP
110
htp://openjdk.java.net/jeps/110
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
• Easy
to
use
API
• Covers
only
the
most
common
use
cases
• Supports
both
HTTP
1.1
and
2
E
40

41. Java
SE
9
Support
for
HTTP/2
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
Small
footprint
• Two
classes
(working
=tles)
– HtpRequestGroup
• configura=on
for
mul=ple
requests
– HtpRequest
• one
request/response
interac=on
E
41

42. Java
SE
9
Support
for
HTTP/2
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
Small
footprint
• Blocking
mode:
one
thread
per
request/response
– send
request
– get
response
• Non-­‐blocking
mode:
handle
mul=ple
request/response
interac=ons
in
single
thread
using
non-­‐blocking
API
– analogous
to
NIO
selectors
E
42

43. Java
SE
9
Support
for
HTTP/2
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
• Responses
handled
through
lambda
style
callback
handlers
– invoked
on
the
calling
thread
– Must
allocate
threads
to
responses
manually
• Request/Response
bodies
handled
as
InputStream/OutputStream
Callback
handlers
E
43

44. Java
SE
9
Support
for
HTTP/2
HttpRequestGroup
group
=
HttpRequestGroup.create();
HttpRequest
req
=
group.createRequest()
.setRequestMethod("POST")
.setRequestURI(new
URI("http://www.foo.com/a/b")
.setRequestBody("Param1=1,Param2=2")
.onResponseHeader("X-­‐Foo",
(request,
name,
value)
-­‐>
{
System.out.printf("
received
an
X-­‐Foo
header");
})
.sendRequest()
.waitForCompletion();
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
E
44

45. Java
SE
9
Support
for
HTTP/2
HttpRequestGroup
group
=
HttpRequestGroup.create();
HttpRequest
req
=
group.createRequest()
…
.onResponseBody((HttpRequest
request,
InputStream
in)
-­‐>
{
if
(request.getResponseCode()
==
200)
{
Path
out
=
Paths.get("/tmp/out");
try
{
Files.copy(in,
out);
}
finally
{
in.close();
}
}
})
.sendRequest()
.waitForCompletion();
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
E
45

46. Java
SE
9
Support
for
HTTP/2
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
HTTP/2
features
• Nego=a=on
of
HTTP/2
from
1.1
– ALPN
or
plaintext
• Server
Push
– Support
for
PUSH_PROMISE
frames
• HPACK
parameters
E
46

47. Our
Plan
for
Your
Time
Investment
Why
HTTP
2?
HTTP
2
Big
Features
How
Servlet
Might
Expose
These
Features
Java
SE
9
Support
for
HTTP
2
Summary
and
Current
Status
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
1
2
3
4
5
S
47

48. Summary
and
Current
Status
• Servlet
4.0
brings
HTTP
2
to
Java
EE
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
– 100%
compliant
implementa=on
of
HTTP
2
– Expose
key
features
to
the
API
• Server
Push
• Stream
Priori=za=on
• Request/Response
mul=plexing
S
48

49. Summary
and
Current
Status
• JSR-­‐369
just
formed
on
22
September
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
• Tenta=ve
Delivery
Schedule
– Q3
2014:
expert
group
formed
– Q1
2015:
early
dra{
– Q3
2015:
public
review
– Q4
2015:
proposed
final
dra{
– Q3
2016:
final
release
S
49

50. Safe
Harbor
Statement
The
preceding
is
intended
to
outline
our
general
product
direc=on.
It
is
intended
for
informa=on
purposes
only,
and
may
not
be
incorporated
into
any
contract.
It
is
not
a
commitment
to
deliver
any
material,
code,
or
func=onality,
and
should
not
be
relied
upon
in
making
purchasing
decisions.
The
development,
release,
and
=ming
of
any
features
or
func=onality
described
for
Oracle’s
products
remains
at
the
sole
discre=on
of
Oracle.
Copyright
©
2014,
Oracle
and/or
its
affiliates.
All
rights
reserved.
|
50