What`s new in Java 7

What's new in
JAVA

Georgian Micsa

About me

Georgian Micsa

- Software engineer with 5+ years of experience,
mainly Java but also .NET and JavaScript
- Interested in OOP, OOD and agile software development
methodologies
- Currently working as a senior Java developer @ Cegeka

- georgian.micsa@gmail.com

- http://ro.linkedin.com/in/georgianmicsa

2

Agenda

Java timeline

Java 7 new features

Future Java 8

References

3

Java timeline

1.0 – January 23, 1996
1.1 – February 19, 1997
Inner classes, JavaBeans, JDBC, RMI, reflection
1.2 – December 8, 1998
Strictfp, Swing, JIT compiler, Java IDL, Collections
1.3 – May 8, 2000
HotSpot JVM, JavaSound, JNDI, JPDA, proxies
1.4 – February 6, 2002
Assert, regex, IPv6, NIO, logger, ImageIO, JAXP, JCE, Java Web Start
5 – September 30, 2004
Generics, annotations, auto/unboxing, enum, varargs, foreach loop, static imports,
skinnable look and feel called Synth, java.util.concurrent, Scanner class
6 – December 11, 2006
Scripting language support, performance improvements for Swing, JAX-WS, JDBC 4.0,
StAX, SwingWorker, table sorting and filtering, double-buffering, JVM improvements, Java Quick
Starter, Java2D uses Direct3D on Windows, Nimbus L&F

4

New features in Java 7
1. Java programming language
2. Java I/O
3. Concurrency
4. Swing
5. Networking
6. Security
7. Collections
8. RIA
9. Java 2D
10. JDBC 4.1
11. JVM
12. java.lang package
13. Java XML
14. I18N

5

Binary Literals:

// An 8-bit 'byte' value:
byte aByte = (byte) 0b00100001;

// A 16-bit 'short' value:
short aShort = (short) 0b1010000101000101;

// Some 32-bit 'int' values:
int anInt1 = 0b10100001010001011010000101000101;
int anInt2 = 0b101;
int anInt3 = 0B101; // The B can be upper or lower case.

// A 64-bit 'long' value. Note the "L" suffix:
long aLong = 0b1000000000000000000001L;

System.out.println(aLong);

6


Underscores in Numeric Literals:

long creditCardNumber = 1234_5678_9012_3456L;
long socialSecurityNumber = 999_99_9999L;
float pi = 3.14_15F;
long hexBytes = 0xFF_EC_DE_5E;
long hexWords = 0xCAFE_BABE;
long maxLong = 0x7fff_ffff_ffff_ffffL;
byte nybbles = 0b0010_0101;
long bytes = 0b11010010_01101001_10010100_10010010;

System.out.println(creditCardNumber);

7


Strings in Switch Statements:

String myString = "tiger";
switch (myString) {
case "crocodile":
System.out.println("Watch out! It`s a reptile!");
break;
case "tiger":
case "lion":
System.out.println("Watch out! It`s a cat!");
break;
default:
System.out.println("Sorry...Animal not identified");
}

8


Type Inference for Generic Instance Creation:

//before 7
Map<String, List<String>> myMap = new HashMap<String, List<String>>();

// DIAMOND operator
//after 7
Map<String, List<String>> myMap2 = new HashMap<>();

9


Automatic Resource Management (ARM):
- Also known as 'try-with-resources' statement
- Resources must implement interface AutoClosable

try (ZipFile zf = new ZipFile("test.zip");
FileInputStream fis = new FileInputStream("test.zip");) {

for (Enumeration entries = zf.entries(); entries.hasMoreElements();) {
String zipEntryName = ((java.util.zip.ZipEntry) entries.nextElement()).getName();
System.out.println(zipEntryName);
}
}

10


Handling more than one type of exception:
// before 7
catch (IOException ex) {
logger.log(ex);
throw ex;
catch (SQLException ex) {
logger.log(ex);
throw ex;
}

// after 7
catch (IOException|SQLException ex) {
logger.log(ex);
throw ex;
}

11

2. Java I/O
- Completely refactored I/O with better performance
- Packages java.nio.file and java.nio.file.attribute: comprehensive support for file I/O
and for accessing the default file system
- The Path class:
Path p1 = Paths.get("/tmp/foo");
Path p3 = Paths.get(URI.create("file:///Users/joe/FileTest.java"));
Path p5 = Paths.get(System.getProperty("user.home"), "logs", "foo.log");
- Checking files: Files.isRegularFile(path); isReadable(path); isExecutable(path); isDirectory(path);
isHidden(path); size(path); getOwner(); etc.
- Delete file or directory: Files.delete(path);
- Copy file or dir: Files.copy(source, target, REPLACE_EXISTING);
- Move/rename file or dir: Files.move(source, target, REPLACE_EXISTING);
- Read file: fileArray = Files.readAllBytes(path);
- Create file: pathFile.newOutputStream(CREATE, APPEND); Files.createFile(path);
- Random access: interface SeekableByteChannel
- The FileSystems class: FileSystems.getDefault().getFileStores()
- Links: Files.createSymbolicLink(newLink, target); Files.createLink(newLink, existingFile);
- Walking the file tree: the FileVisitor interface
- Finding files: FileSystems.getDefault().getPathMatcher("glob:*.{java,class}");
- Coexistence with legacy code: Path input = file.toPath();
- Custom File System Providers: ex. JAR file system provider
12

2. Java I/O
Directory Watch Service:
WatchService watcher = FileSystems.getDefault().newWatchService();
WatchKey key = dir.register(watcher, StandardWatchEventKinds.ENTRY_CREATE,
StandardWatchEventKinds.ENTRY_DELETE, StandardWatchEventKinds.ENTRY_MODIFY);
for (;;) {
//wait for key to be signaled
try {
key = watcher.take();
} catch (InterruptedException x) {
return;
}

for (WatchEvent<?> event : key.pollEvents()) {
WatchEvent.Kind<?> kind = event.kind();

//This key is registered only for ENTRY_CREATE events,
//but an OVERFLOW event can occur regardless if events are
//lost or discarded.
if (kind == StandardWatchEventKinds.OVERFLOW) {
continue;
}

//The filename is the context of the event.
WatchEvent<Path> ev = (WatchEvent<Path>) event;
Path filename = ev.context();
….

13

2. Java I/O
Non-blocking I/O or asynchronous I/O:

A. Return Future representing pending result:

AsynchronousSocketChannel ch = ...
Future<Integer> result = ch.read(buf);
int nread = result.get();
B. CompletionHandler invoked when I/O completes:

interface CompletionHandler<V,A> {
void completed(V result, A attachment);
void failed(Throwable exc, A attachment);
}
ch.read(buf, conn, handler);

- New classes: AsynchronousSocketChannel, AsynchronousServerSocketChannel,
AsynchronousDatagramChannel, AsynchronousFileChannel

- Async operations: READ/WRITE, CONNECT, ACCEPT, RECEIVE/SEND,

14

3. Concurrency
Fork-join framework:
- parallel programming
- based on the ForkJoinPool class (Executor)
- work-stealing technique for the workers
- divide and conquer problems: RecursiveTask and RecursiveAction classes

class ForkSum extends RecursiveTask<Long> {
@Override
protected Long compute() {
if (toIndex - fromIndex <= DIRECT_COMPUTE_SIZE) {
return computeDirectly();
}
int split = (fromIndex + toIndex) / 2;
ForkSum f1 = new ForkSum(array, fromIndex, split);
f1.fork();
ForkSum f2 = new ForkSum(array, split + 1, toIndex);
f2.fork();
return f2.join() + f1.join();
}

//MAIN:
ForkSum forkSum = new ForkSum(computeArray, 0, N - 1);
ForkJoinPool pool = new ForkJoinPool(); // uses number of cores
Long result = pool.invoke(forkSum);

15

3. Concurrency

- The ThreadLocalRandom class eliminates contention among threads using pseudo-random numbers
- For concurrent access (fork-join framework), using ThreadLocalRandom instead of Math.random()
results in less contention and, ultimately, better performance.

int r = ThreadLocalRandom.current().nextInt(4, 77);

- The Phaser class is a new synchronization barrier, similar to CyclicBarrier
- More flexible usage
- Number of parties registered to synchronize on a phaser may vary over time: register(), bulkRegister(),
arriveAndDeregister();
- Better synchronization: arriveAndAwaitAdvance(), arrive(), arriveAndDeregister(),
awaitAdvance(int phase)
- Termination: isTerminated(), forceTermination()
- Monitoring: getRegisteredParties(), getArrivedParties(), getPhase(), getUnarrivedParties()
- Tiering: Build phasers in tree structure to reduce contention.

16

4. Swing
- The JLayer class has been added, which is a flexible and powerful decorator for Swing components
- You can draw effects, blurring, animating a busy indicator, validate textfields, respond to events etc.
JFrame f = new JFrame();
JPanel panel = createPanel();
LayerUI<JPanel> layerUI = new WallpaperLayerUI();
JLayer<JPanel> jlayer = new JLayer<JPanel>(panel, layerUI);
f.add (jlayer);

class WallpaperLayerUI extends LayerUI<JComponent> {
public void paint(Graphics g, JComponent c) {
...
}
}

- The Nimbus Look and Feel has been moved from the com.sun.java.swing package
to the javax.swing package
- Mixing Heavyweight and Lightweight Components is easier to accomplish
- Windows with transparency and non-rectangular shape are supported
// Set the window to 55% opaque (45% translucent).
w.setOpacity(0.55f);
// Shaped windows
w.setShape(new Ellipse2D.Double(0,0,getWidth(),getHeight()));
- An HSV tab has been added to the JColorChooser class

17

5. Networking
- The URLClassLoader.close() method has been added
- Invalidates the loader
- It also closes any JAR files - this allows the application to delete or replace these files

- The Sockets Direct Protocol (SDP) provides access to high performance network connections
- Introduced in 1999 by the InfiniBand Trade Association,
InfiniBand (IB) was created to address the need for high performance computing
- Remote Direct Memory Access (RDMA):
- enables moving data directly from the memory of one computer to another computer
- bypassing the operating system of both computers
- resulting in significant performance gains
- SDP supports stream connections over InfiniBand fabric
- No API changes required in JDK
- The implementation of SDP is transparent and supported by the classic networking and new I/O
- You only have to create a configuration file. Example:
# Use SDP when binding to 192.0.2.1
bind 192.0.2.1 *
# Use SDP when connecting to all application services on 192.0.2.*
connect 192.0.2.0/24 1024-*

18

6. Security

- Support for Elliptic Curve Cryptography (ECC)

- A new native provider has been added that provides several ECC-based algorithms (ECDSA/ECDH):
- DSA Signatures using ECC
- Key agreement: Diffie-Hellman key exchange using ECC

- Weak cryptographic algorithms can now be disabled, for example MD2

- Various enhancements related to SSL/TLS have been added to Java Secure Socket Extension

19

7. Collections

- The TransferQueue interface has been added
- A refinement of the BlockingQueue interface:
- producers may wait for consumers to receive elements
- transfer(E e)
- tryTransfer(E e)
- tryTransfer(E e, long timeout, TimeUnit unit)
- getWaitingConsumerCount()
- hasWaitingConsumer()
- The class LinkedTransferQueue implements the TransferQueue interface

20

8. RIA

- The window of a dragged applet can be decorated with a default or custom title
- Enhancements have been made to the syntax of JNLP files:
- The os attribute in the information and resources elements can now contain
specific versions of Windows
- Applications can use the install attribute in the shortcut element
- Java Web Start applications can be deployed without specifying the codebase attribute
- A JNLP file can be embedded into an HTML page:
<script src="http://www.java.com/js/deployJava.js"></script>
<script>
var attributes = {} ;

var parameters = {jnlp_href: 'dynamictree-applet.jnlp',
jnlp_embedded: 'PCEtLSAKLyoKICogQ29weX ... HA+Cg=='
};
deployJava.runApplet(attributes, parameters, '1.6');
</script>
- You can check the status variable of the applet while it is loading to determine
if the applet is ready to handle requests from JavaScript code

21

9. Java 2D

- A new XRender-based Java 2D rendering pipeline is supported for modern X11-based desktops,
offering improved graphics performance:

-Dsun.java2d.xrender=true

- The JDK now enumerates and displays installed OpenType/CFF fonts
through methods such as GraphicsEnvironment.getAvailableFontFamilyNames

22

10. JDBC 4.1

- The ability to use a try-with-resources statement to automatically close
resources of type Connection, ResultSet, and Statement:
try (Statement stmt = con.createStatement()) {

// ...

}

- RowSet 1.1: The introduction of the RowSetFactory interface and the RowSetProvider class
- Enable you to create all types of row sets supported by your JDBC driver
- JdbcRowSet:
- enhanced ResultSet object
- it maintains a connection to its data source
- it has a set of properties and a listener notification mechanism
- it makes a ResultSet object scrollable and updatable
- The RowSetFactory interface:
- createCachedRowSet
- createFilteredRowSet
- createJdbcRowSet
- createJoinRowSet
- createWebRowSet

23

11. JVM
JVM Support for Non-Java Languages
- Dynamically typed language => type checking at runtime
- New JVM instruction that simplifies the implementation of dynamically typed
programming languages on the JVM: invokedynamic
- Allows the language implementer to define custom linkage behavior
- Define bootstrap method that links the invokedynamic call site to the “real” method
Garbage-First Collector
- Server-style garbage collector that replaces the Concurrent Mark-Sweep Collector (CMS)
- Targeted for multi-processors with large memories, decrease pause times and increase throughput
- Marking and evacuation is performed on parallel on multi-processors
- G1 partitions the Heap in equal size regions and compacts them
- G1 first collects and compacts the regions full of reclaimable objects
- More predictable garbage collection pauses than CMS
- User can set the desired pause targets
Java HotSpot Virtual Machine Performance Enhancements
- Tiered Compilation => speed up the server VM: -server -XX:+TieredCompilation
- Compressed Oops – managed pointers for objects offsets and not byte offsets
- Escape analysis
- compiler may eliminate certain object allocations
- compiler may eliminate synchronization blocks (lock elision)
- NUMA Collector enhancements for the parallel GC
24

java.lang, XML & I18N

12. java.lang package
- Potential deadlocks were eliminated for multithreaded, non-hierarchically delegating
custom class loaders

13. Java XML
- Java API for XML Processing (JAXP) 1.4.5,
- Java Architecture for XML Binding (JAXB) 2.2.3,
- Java API for XML Web Services (JAX-WS) 2.2.4

14. I18N
- Support for Unicode 6.0.0:
- over 2000 additional characters, as well as support for properties and data files
- by default in Java 1 char = 16 bits => only 65536 characters
- supplementary characters are defined as a pair of char values, from 0x10000 to 0x10FFFF
- Extensible Support for ISO 4217 Currency Codes: currency.properties
- Category Locale Support: 2 types of category: Locale.Category FORMAT and DISPLAY
- Unicode 6.0 Support in Regular Expressions API

25

Future Java 8

- Modularization of the JDK under Project Jigsaw
- Parts of project Coin that are not included in Java 7
- Language-level support for lambda expressions
(officially, lambda expressions; unofficially, closures)
under Project Lambda:
Collection collection = ... ;
collection.sortBy(#{ Foo f -> f.getLastName() });
collection.remove(#{ Foo f -> f.isBlue() });
- Annotations on Java Types:
Map<@NonNull String, @NonEmpty List<@Readonly Document>> files;
- New Date and Time API

26

References
Java Timeline:
http://www.oracle.com/technetwork/java/javase/overview/javahistory-timeline-
198369.html
Java 7:
http://download.oracle.com/javase/7/docs/
NIO 2:
http://openjdk.java.net/projects/nio/presentations/TS-5686.pdf
SWING:
http://download.oracle.com/javase/tutorial/uiswing/misc/jlayer.html
Networking:
http://download.oracle.com/javase/tutorial/sdp/sockets/index.html
JVM:
http://download.oracle.com/javase/7/docs/technotes/guides/vm/multiple-language-
support.html
http://download.oracle.com/javase/7/docs/technotes/guides/vm/performance-
enhancements-7.html
Java 8:
http://jcp.org/en/jsr/detail?id=337

27

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