Java7 - Top 10 Features

  • 9,005 views
Uploaded on

My top 10 features in Java SE 7

My top 10 features in Java SE 7

  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
  • what is the procedure to download the slides......i can't download it
    Are you sure you want to
    Your message goes here
  • Thanks for the Java 7 features and you can solved examples here - www.javadiscover.blogspot.com/search/label/Java%207
    Are you sure you want to
    Your message goes here
No Downloads

Views

Total Views
9,005
On Slideshare
0
From Embeds
0
Number of Embeds
2

Actions

Shares
Downloads
216
Comments
2
Likes
11

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. Java SE 7 {finally}
    2011-08-18
    Andreas Enbohm
  • 2. 19 augusti 2011
    Sida 2
    Java SE 7
    A evolutionaryevolement of Java
    6 yearssince last update
    Somethingsleftout, will briefly discuss this at the end
    Oracle reallypushing Java forward- a lotpolitical problems with Sun made Java 7 postphonedseveraltimes
    Java still growing (1.42%), #1 mostusedlanguageaccording to TIOBE with 19.4% (Aug 2011)
    My top 10 new features (not ordered in anyway)
  • 3. Java SE 7 – Language Changes
    Number 1:Try-with-resources Statement (or ARM-blocks)
    Before :
    19 augusti 2011
    Sida 3
    static String readFirstLineFromFileWithFinallyBlock(String path) throwsIOException {
    BufferedReaderbr = new BufferedReader(new FileReader(path));
    try {
    returnbr.readLine();
    } finally {
    if (br != null) {
    try {
    br.close();
    } catch (IOExceptionignore){
    //donothing
    }
    }
    }
    }
  • 4. Java SE 7 – Language Changes
    Number 1:Try-with-resources Statement (or ARM-blocks)
    With Java 7:
    19 augusti 2011
    Sida 4
    static String readFirstLineFromFile(String path) throws IOException {
    try (BufferedReaderbr = new BufferedReader(new FileReader(path))) {
    return br.readLine();
    }
    }
  • 5. Java SE 7 – Language Changes
    Number 1 - NOTE:
    The try-with-resources statement is a try statement that declares one or more resources. A resource is as an object that must be closed after the program is finished with it.
    The try-with-resources statement ensures that each resource is closed at the end of the statement.
    Any object that implements java.lang.AutoCloseable, which includes all objects which implement java.io.Closeable, can be used as a resource.
    19 augusti 2011
    Sida 5
  • 6. Java SE 7 – Language Changes
    Number 2: Strings in switch Statements
    19 augusti 2011
    Sida 6
    public String getTypeOfDayWithSwitchStatement(String dayOfWeekArg) {
    String typeOfDay;
    switch (dayOfWeekArg) {
    case "Monday":
    typeOfDay = "Start of work week";
    break;
    case "Tuesday":
    case "Wednesday":
    case "Thursday":
    typeOfDay = "Midweek";
    break;
    case "Friday":
    typeOfDay = "End of work week";
    break;
    case "Saturday":
    case "Sunday":
    typeOfDay = "Weekend";
    break;
    default:
    throw new IllegalArgumentException("Invalid day of the week: " + dayOfWeekArg);
    }
    return typeOfDay;
    }
  • 7. Java SE 7 – Language Changes
    Number 2 - NOTE:
    The Java compiler generates generally more efficient bytecode from switch statements that use String objects than from chained if-then-else statements.
    19 augusti 2011
    Sida 7
  • 8. Java SE 7 – Language Changes
    Number 3:Catching Multiple ExceptionTypes
    Before :
    Difficult to eliminatecodeduplicationdue to different exceptions!
    19 augusti 2011
    Sida 8
    try {

    } catch (IOException ex) {
    logger.log(ex);
    throw ex;
    } catch (SQLException ex) {
    logger.log(ex);
    throw ex;
    }
  • 9. Java SE 7 – Language Changes
    Number 3:Catching Multiple ExceptionTypes
    With Java 7 :
    19 augusti 2011
    Sida 9
    try {

    } catch (IOException|SQLException ex) {
    logger.log(ex);
    throw ex;
    }
  • 10. Java SE 7 – Language Changes
    Number 3 - NOTE:Catching Multiple ExceptionTypes
    Bytecode generated by compiling a catch block that handles multiple exception types will be smaller (and thus superior) than compiling many catch blocks that handle only one exception type each.
    19 augusti 2011
    Sida 10
  • 11. Java SE 7 – Language Changes
    Number 4:TypeInference for GenericInstance Creation
    Before:
    Howmanytimeshave you swornabout this duplicatedcode? 
    19 augusti 2011
    Sida 11
    Map<String, List<String>> myMap = new HashMap<String, List<String>>();
  • 12. Java SE 7 – Language Changes
    Number 4:TypeInference for GenericInstance Creation
    With Java 7:
    19 augusti 2011
    Sida 12
    Map<String, List<String>> myMap = new HashMap<>();
  • 13. Java SE 7 – Language Changes
    Number 4 - NOTE:TypeInference for GenericInstance Creation
    Writing new HashMap() (withoutdiamond operator) will still use the rawtype of HashMap (compilerwarning)
    19 augusti 2011
    Sida 13
  • 14. Java SE 7 – Language Changes
    Number 5:Underscores in NumericLiterals
    19 augusti 2011
    Sida 14
    longcreditCardNumber = 1234_5678_9012_3456L;
    longsocialSecurityNumber = 1977_05_18_3312L;
    float pi = 3.14_15F;
    longhexBytes = 0xFF_EC_DE_5E;
    longhexWords = 0xCAFE_BABE;
    longmaxLong = 0x7fff_ffff_ffff_ffffL;
    long bytes = 0b11010010_01101001_10010100_10010010;
  • 15. Java SE 7 – Language Changes
    Number 5 - NOTE:Underscores in NumericLiterals
    You can place underscores only between digits; you cannot place underscores in the following places:
    At the beginning or end of a number
    Adjacent to a decimal point in a floating point literal
    Prior to an F or L suffix
    In positions where a string of digits is expected
    19 augusti 2011
    Sida 15
  • 16. Java SE 7 – ConcurrentUtilities
    Number 6:Fork/JoinFramework (JSR 166)
    ” a lightweightfork/joinframework with flexible and reusablesynchronizationbarriers, transfer queues, concurrent linked double-endedqueues, and thread-localpseudo-random-number generators.”
    19 augusti 2011
    Sida 16
  • 17. Java SE 7 – ConcurrentUtilities
    Number 6:Fork/JoinFramework (JSR 166)
    19 augusti 2011
    Sida 17
    if (my portion of the work is small enough)
    do the work directly
    else
    split my work into two pieces invoke the two pieces and wait for the results
  • 18. Java SE 7 – ConcurrentUtilities
    Number 6:Fork/JoinFramework (JSR 166)
    19 augusti 2011
    Sida 18
  • 19. Java SE 7 – ConcurrentUtilities
    Number 6:Fork/JoinFramework (JSR 166)
    New Classes
    19 augusti 2011
    Sida 19
  • 24. Java SE 7 – Filesystem API
    Number 7: NIO 2 Filesystem API (Non-Blocking I/O)
    Bettersupports for accessingfile systems such and support for customfile systems (e.g. cloudfile systems)
    Access to metadata such as file permissions
    Moreeffecient support whencopy/movingfiles
    EnchancedExceptionswhenworking on files, i.e. file.delete() nowthrowsIOException (not just Exception)
    19 augusti 2011
    Sida 20
  • 25. Java SE 7 – JVM Enhancement
    Number 8:InvokeDynamic (JSR292)
    Support for dynamiclanguages so theirperformance levels is near to that of the Java language itself
    At byte code level this means a new operand (instruction) called invokedynamic
    Make is possible to do efficient method invocation for dynamic languages (such as JRuby) instead of statically (like Java) .
    Huge performance gain
    19 augusti 2011
    Sida 21
  • 26. Java SE 7 – JVM Enhancement
    Number 9: G1 and JVM optimization
    G1 morepredictable and uses multiple coresbetterthan CMS
    Tiered Compilation –Bothclient and server JIT compilers are usedduringstarup
    NUMA optimization - Parallel Scavenger garbage collector has been extended to take advantage of machines with NUMA (~35% performance gain)
    EscapeAnalysis - analyze the scope of a new object's and decide whether to allocate it on the Java heap
    19 augusti 2011
    Sida 22
  • 27. Java SE 7 – JVM Enhancement
    Number 9:EscapeAnalysis
    19 augusti 2011
    Sida 23
    public class Person {
    private String name; private int age;
    public Person(String personName, intpersonAge) {
    name = personName; age = personAge; }
    public Person(Person p) {
    this(p.getName(), p.getAge());
    }
    }
    public classEmployee {
    private Person person; // makes a defensive copy to protectagainstmodifications by caller
    public Person getPerson() {
    return new Person(person)
    };
    public voidprintEmployeeDetail(Employeeemp) {
    Person person = emp.getPerson(); // this callerdoes not modify the object, so defensive copywasunnecessary
    System.out.println ("Employee'sname: " + person.getName() + "; age: " + person.getAge()); }
    }
  • 28. Java SE 7 - Networking
    Number 10: Support for SDP 
    SocketDirectProtocol (SDP) enablesJVMs to use Remote Direct Memory Access (RDMA). RDMA enables moving data directly from the memory of one computer to another computer, bypassing the operating system of both computers and resulting in significant performance gains.
    The result is High throughput and Low latency (minimal delay between processing input and providing output) such as you would expect in a real-time application.
    19 augusti 2011
    Sida 24
  • 29. Java SE 7 - Networking
    Number 10 - NOTE: Support for SDP
    The Sockets Direct Protocol (SDP) is a networking protocol developed to support stream connections over InfiniBand fabric.
    Solaris 10 5/08 has support for InfiniBand fabric (which enables RDMA). On Linux, the InfiniBand package is called OFED (OpenFabrics Enterprise Distribution).
    19 augusti 2011
    Sida 25
  • 30. Java SE 7
    A complete list of all new features can be seen on http://www.oracle.com/technetwork/java/javase/jdk7-relnotes-418459.html
    19 augusti 2011
    Sida 26
  • 31. Java SE 8
    Some features whereleftout in Java 7; mostimportant are Project Lambda (closures) and Project Jigsaw (modules) targeted for Java 8 (late 2012)
    Lambdas (and extension methods) willprobably be the biggestsinglechangeevermade on the JVM. Will introduce a powerfulprogrammingmodel, however it comes with a great deal of complexity as well.
    Moduleswillmade it easier to version modules (no moreJAR-hell) and introducea new way of definingclasspaths
    19 augusti 2011
    Sida 27
  • 32. Java SE 7 & 8
    Questions?
    19 augusti 2011
    Sida 28