Java:Features of JDK 5,JDK 6 and JDK 7

Features of JDK 5,JDK 6 and JDK 7: 

JDK 5: Codename:Tiger

·         Introduced Generics ( Provides compile-time (static) type safety for collections and eliminates the need for most typecasts (type conversion)).

·         Metadata: Also called annotations; allows language constructs such as classes and methods to be tagged with additional data, which can then be processed by metadata-aware utilities.

·         Autoboxing/unboxing: Automatic conversions between primitive types (such as int) and primitive wrapper classes (such as Integer).

·         Enumerations: The enum keyword creates a typesafe, ordered list of values (such as Day.MONDAY, Day.TUESDAY, etc.). Previously this could only be achieved by non-typesafe constant integers or manually constructed classes (typesafe enum pattern)

·         Varargs: The last parameter of a method can now be declared using a type name followed by three dots (e.g. void drawtext(String... lines)). In the calling code any number of parameters of that type can be used and they are then placed in an array to be passed to the method, or alternatively the calling code can pass an array of that type.

·         Enhanced for each loop: The for loop syntax is extended with special syntax for iterating over each member of either an array or any Iterable, such as the standard Collection classes.

·         Fix the previously broken semantics of the Java Memory Model, which defines how threads interact through memory.

·         Static imports (that allows members (fields and methods) defined in a class as public static to be used in Java code without specifying the class in which the field is defined)

·         Automatic stub generation for RMI objects.

·         Swing: New skinnable look and feel, called synth.

·         The concurrency utilities in package java.util.concurrent.

·         Scanner class for parsing data from various input streams and buffers. 

JDK 6: Codename:Mustang

·         Generic API for tight integration with scripting languages, and built-in Mozilla JavaScript Rhino integration

·         Dramatic performance improvements for the core platform,and Swing. Many GUI improvements, such as integration of SwingWorker in the API, table sorting and filtering, and true Swing double-buffering (eliminating the gray-area effect).

·         Improved Web Service support through JAX-WS

·         JDBC 4.0 support

·         Java Compiler API ::an API allowing a Java program to select and invoke a Java Compiler programmatically.

·         Upgrade of JAXB to version 2.0

·         Support for pluggable annotations

·         JVM improvements include: synchronization and compiler performance optimizations, new algorithms and upgrades to existing garbage collection algorithms, and application start-up performance

JDK 7: Codename:Dolphin

·         JVM support for dynamic languages, following the prototyping work currently done on the Multi Language Virtual Machine

·         Small language changes (grouped under a project named Coin)

·         Strings in switch

·         Automatic resource management in try-statement

·         Improved type inference for generic instance creation

·         Simplified varargs method declaration

·         Binary integer literals

·         Allowing underscores in numeric literals

·         Catching multiple exception types and rethrowing exceptions with improved type checking

·         New file I/O library to enhance platform independence and add support for metadata and symbolic links. The new packages are java.nio.file and java.nio.file.attribute.

·         Library-level support for elliptic curve cryptography algorithms

·         An XRender pipeline for Java 2D, which improves handling of features specific to modern GPUs

·         New platform APIs for the graphics features originally implemented in version 6u10 as unsupported APIs

·         Enhanced library-level support for new network protocols, including SCTP and Sockets Direct Protocol

·         Upstream updates to XML and Unicode