Java 5 and 6 New Features

Java
5
&
6
Features

Jussi
Pohjolainen

Tampere
University
of
Applied
Sciences

Versions
and
Naming

•  JDK
1.0
–
1996

•  JDK
1.1
–
1997
–
JDBC,
RMI,
ReﬂecQon..

•  J2SE
1.2
–
1998
–
Swing,
CollecQons..

•  J2SE
1.3
-‐
2000
–
HotSpot
JVM..

•  J2SE
1.4
–
2002
–
assert,
NIO,
Web
start..

•  J2SE
5.0
(1.5)
–
2004
–
Generics,
Autoboxing..

•  Java
SE
6
(1.6)
–
2006
–
Rhino,
JDBC
4.0
…

•  Java
SE
7
(1.7)
–
2011
–
Small
language
changes,

API
Changes

New
Features

•  Java
SE
5

–  Generics

–  Autoboxing

–  Improved
looping
syntax

–  AnnotaQons

–  …

•  Java
SE
6

–  XML
Processing
and
Web
Services

–  ScripQng

–  JDBC
4.0

–  Desktop
APIs

–  …

Generics

ArrayList list = new ArrayList();
list.add("a");
list.add("b");
list.add(new Integer(22));

Iterator i = list.iterator();

while(i.hasNext()) {
System.out.println((String) i.next());
}

Using
Generics

ArrayList<String> list = new ArrayList<String>();
list.add("a");
list.add("b");

Iterator<String> i = list.iterator();

while(i.hasNext()) {
System.out.println((String) i.next());
}

Enhanced
for
-‐
loop

ArrayList<String> list = new ArrayList<String>();
list.add("a");
list.add("b");
list.add("c");

// Loop array or collection. Iteration used
// even without declaration! The list object
// must implement java.lang.Iterable interface
for(String alphabet : list) {
System.out.println(alphabet);
}

Java
1.4

import java.util.*;

class Main {
public static void main(String [] args) {
// Does not work, 5 is not a Object type!
someMethod(5);
}

public static void someMethod(Object a) {
System.out.println(a.toString());
}
}

Java
1.4:
SoluQon

import java.util.*;

class Main {
Integer temp = new Integer(5);
someMethod(temp);
}

}
}

Java
1.4:
Lot
of
Coding

Integer a = new Integer(5);
Integer b = new Integer(6);
int aPrimitive = a.intValue();
Int bPrimitive = b.intValue();

Autoboxing
Comes
to
Rescue!

class Main {
// Boxing
Integer a = 2;

// UnBoxing
int s = 5 + a;
}
}

Java
1.5

class Main {
// Works!
someMethod(5);
}

}
}

Java
1.5

import java.util.*;

class Main {
ArrayList<Integer> list = new ArrayList<Integer>();
list.add(5);
list.add(7);

for(int number : list) {
System.out.println(number);
}
}
}

Enum

•  An
enum
type
is
a
type
whose
ﬁelds
consist
of

a
ﬁxed
set
of
constants

enum Color {
WHITE, BLACK, RED, YELLOW, BLUE;
}

Usage

enum Color {
}

class Main {
System.out.println(Color.WHITE);

Color c1 = Color.RED;
System.out.println(c1);
}

Enum

•  Enum
declaraQon
deﬁnes
a
class!

•  Enum
can
include
methods

•  Enum
constants
are
ﬁnal
staQc

•  Compiler
adds
special
methods
like
values

that
returns
an
array
containing
all
the
values

of
the
enum.

•  Enum
class
extends
java.lang.enum

Enum

enum Color {
}

class Main {
for (Color c : Color.values()) {
System.out.println(c);
}
}
}

StaQc
Import
(1/2)

class Main {
int x = Integer.parseInt("55");
int y = Integer.parseInt("56");
int x = Integer.parseInt("57");
}
}

StaQc
Import
(2/2)

import static java.lang.Integer.parseInt;

class Main {
int x = parseInt("55");
int y = parseInt("56");
int z = parseInt("57");
}
}

Metadata

•  With
Java
5
it’s
possible
to
add
metadata
to

methods,
parameters,
ﬁelds,
variables..

•  Metadata
is
given
by
using
annota,ons

•  Many
annota.ons
replace
what
would

otherwise
have
been
comments
in
code.

•  Java
5
has
built-‐in
annotaQons

Override:
Does
not
Compile!

class Human {
public void eat() {
System.out.println("Eats food");
}
}

class Programmer extends Human {
@Override
public void eatSomeTypo() {
System.out.println("Eats pizza");
}
}

class Main {
Programmer jack = new Programmer();
jack.eat();
}
}

Other
AnnotaQons
used
By
Compiler

•  @Depricated
–
Gives
warning
if
when

depricated
method
or
class
is
used

•  @SuppressWarnings
–
Suppress
all
warnings

that
would
normally
generate

System.out.format

import java.util.Date;

class Main {
Date d = new Date();
// Lot of format characters available!
System.out.format("Today is %TF", d);
}
}

Variable
Argument
List

class Main {
public static void printGreeting(String... names) {
for (String n : names) {
System.out.println("Hello " + n + ". ");
}
}

public static void main(String[] args) {
String [] names = {"Jack", "Paul"};

printGreeting("Jack", "Paul");
printGreeting(names);
}
}

User
Input:
Scanner

Scanner in = new Scanner(System.in);
int a = in.nextInt();

Java
6:
XML
&
Web
Services

•  Easy
way
of
creaQng
Web
Services

•  Expose
web
service
with
a
simple
annotaQon

Web
Service

package hello;

import javax.jws.WebService;

@WebService

public class CircleFunctions {
public double getArea(double r) {
return java.lang.Math.PI * (r * r);
}

public double getCircumference(double r) {
return 2 * java.lang.Math.PI * r;
}
}

Server

import javax.xml.ws.Endpoint;

class Publish {

Endpoint.publish(
"http://localhost:8080/circlefunctions",
new CircleFunctions());

}

Generate
Stub
Files

•  Generate
stub
ﬁles:

–  wsgen
–cp
.
hello.CircleFuncQons

Java
6:
Rhino

•  Framework
to
connect
to
Java
programs
to

scripQng-‐language
interpreters.

•  Rhino
JS
Engine
comes
with
Java
6

•  To
ability
to
run
JS
from
Java
and
JS
from

command
line

•  Rhino
is
wriken
in
Java

Example

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

public class Main {
ScriptEngineManager mgr = new ScriptEngineManager();
ScriptEngine engine = mgr.getEngineByName("JavaScript");

// Now we have a script engine instance that
// can execute some JavaScript
try {
engine.eval("print('Hello')");
} catch (ScriptException ex) {
ex.printStackTrace();
}
}
}

Java
6:
GUI

•  Faster
Splash
Screens

•  System
tray
support

•  Improved
Drag
and
Drop

•  Improved
Layout

•  WriQng
of
Gif
-‐
ﬁles

Java
6:
DB
Support

•  Java
6
comes
with
preinstalled
relaQonal

database,
Oracle
release
of
Apache
Derby

Project

•  Java
DB
is
installed
automaQcally
as
part
of

the
Java
SE
Development
Kit
(JDK).

•  For
a
Java
DB
installaQon,
set
the

DERBY_HOME
environment
variable

Java
7

•  Using
Strings
in
switch
statements

•  Syntax
for
automaQc
cleaning
of
streams

•  Numeric
literals
with
underscores

•  OR
in
excepQon
catches

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