New features in java 7 - java-7

Question

What new features in java 7 is going to be implemented?
And what are they doing now?

Answer 1

Java SE 7 Features and Enhancements from JDK 7 Release Notes
This is the Java 7 new features summary from the OpenJDK 7 features page:
vm JSR 292: Support for dynamically-typed languages (InvokeDynamic)
Strict class-file checking
lang JSR 334: Small language enhancements (Project Coin)
core Upgrade class-loader architecture
Method to close a URLClassLoader
Concurrency and collections updates (jsr166y)
i18n Unicode 6.0
Locale enhancement
Separate user locale and user-interface locale
ionet JSR 203: More new I/O APIs for the Java platform (NIO.2)
NIO.2 filesystem provider for zip/jar archives
SCTP (Stream Control Transmission Protocol)
SDP (Sockets Direct Protocol)
Use the Windows Vista IPv6 stack
TLS 1.2
sec Elliptic-curve cryptography (ECC)
jdbc JDBC 4.1
client XRender pipeline for Java 2D
Create new platform APIs for 6u10 graphics features
Nimbus look-and-feel for Swing
Swing JLayer component
Gervill sound synthesizer [NEW]
web Update the XML stack
mgmt Enhanced MBeans [UPDATED]
Code examples for new features in Java 1.7
Try-with-resources statement
this:
BufferedReader br = new BufferedReader(new FileReader(path));
try {
return br.readLine();
} finally {
br.close();
}
becomes:
try (BufferedReader br = new BufferedReader(new FileReader(path)) {
return br.readLine();
}
You can declare more than one resource to close:
try (
InputStream in = new FileInputStream(src);
OutputStream out = new FileOutputStream(dest))
{
// code
}
Underscores in numeric literals
int one_million = 1_000_000;
Strings in switch
String s = ...
switch(s) {
case "quux":
processQuux(s);
// fall-through
case "foo":
case "bar":
processFooOrBar(s);
break;
case "baz":
processBaz(s);
// fall-through
default:
processDefault(s);
break;
}
Binary literals
int binary = 0b1001_1001;
Improved Type Inference for Generic Instance Creation
Map<String, List<String>> anagrams = new HashMap<String, List<String>>();
becomes:
Map<String, List<String>> anagrams = new HashMap<>();
Multiple exception catching
this:
} catch (FirstException ex) {
logger.error(ex);
throw ex;
} catch (SecondException ex) {
logger.error(ex);
throw ex;
}
becomes:
} catch (FirstException | SecondException ex) {
logger.error(ex);
throw ex;
}
SafeVarargs
this:
#SuppressWarnings({"unchecked", "varargs"})
public static void printAll(List<String>... lists){
for(List<String> list : lists){
System.out.println(list);
}
}
becomes:
#SafeVarargs
public static void printAll(List<String>... lists){
for(List<String> list : lists){
System.out.println(list);
}
}

Answer 2

New Feature of Java Standard Edition (JSE 7)
Decorate Components with the JLayer Class:
The JLayer class is a flexible and powerful decorator for Swing components. The JLayer class in Java SE 7 is similar in spirit to the JxLayer project project at java.net. The JLayer class was initially based on the JXLayer project, but its API evolved separately.
Strings in switch Statement:
In the JDK 7 , we can use a String object in the expression of a switch statement. The Java compiler generates generally more efficient bytecode from switch statements that use String objects than from chained if-then-else statements.
Type Inference for Generic Instance:
We can replace the type arguments required to invoke the constructor of a generic class with an empty set of type parameters (<>) as long as the compiler can infer the type arguments from the context. This pair of angle brackets is informally called the diamond.
Java SE 7 supports limited type inference for generic instance creation; you can only use type inference if the parameterized type of the constructor is obvious from the context. For example, the following example does not compile:
List<String> l = new ArrayList<>();
l.add("A");
l.addAll(new ArrayList<>());
In comparison, the following example compiles:
List<? extends String> list2 = new ArrayList<>();
l.addAll(list2);
Catching Multiple Exception Types and Rethrowing Exceptions with Improved Type Checking:
In Java SE 7 and later, a single catch block can handle more than one type of exception. This feature can reduce code duplication. Consider the following code, which contains duplicate code in each of the catch blocks:
catch (IOException e) {
logger.log(e);
throw e;
}
catch (SQLException e) {
logger.log(e);
throw e;
}
In releases prior to Java SE 7, it is difficult to create a common method to eliminate the duplicated code because the variable e has different types.
The following example, which is valid in Java SE 7 and later, eliminates the duplicated code:
catch (IOException|SQLException e) {
logger.log(e);
throw e;
}
The catch clause specifies the types of exceptions that the block can handle, and each exception type is separated with a vertical bar (|).
The java.nio.file package
The java.nio.file package and its related package, java.nio.file.attribute, provide comprehensive support for file I/O and for accessing the file system. A zip file system provider is also available in JDK 7.
Source: http://ohmjavaclasses.blogspot.com/

Answer 3

Java Programming Language Enhancements # Java7
Binary Literals
Strings in switch Statement
Try with Resources (How it works) or ARM (Automatic Resource Management)
Multiple Exception Handling
Suppressed Exceptions
underscore in literals
Type Inference for Generic Instance Creation using Diamond Syntax
Improved Compiler Warnings and Errors When Using Non-Reifiable Formal Parameters with Varargs Methods
Official reference
Official reference with java8
wiki reference

Answer 4

In addition to what John Skeet said, here's an overview of the Java 7 project. It includes a list and description of the features.
Note: JDK 7 was released on July 28, 2011, so you should now go to the official java SE site.

Answer 5

Language changes:
-Project Coin (small changes)
-switch on Strings
-try-with-resources
-diamond operator
Library changes:
-new abstracted file-system API (NIO.2) (with support for virtual filesystems)
-improved concurrency libraries
-elliptic curve encryption
-more incremental upgrades
Platform changes:
-support for dynamic languages
Below is the link explaining the newly added features of JAVA 7 , the explanation is crystal clear with the possible small examples for each features :
http://radar.oreilly.com/2011/09/java7-features.html

Answer 6

Using Diamond(<>) operator for generic instance creation
Map<String, List<Trade>> trades = new TreeMap <> ();
Using strings in switch statements
String status= “something”;
switch(statue){
case1:
case2:
default:
}
Underscore in numeric literals
int val 12_15;
long phoneNo = 01917_999_720L;
Using single catch statement for throwing multiple exception by using “|” operator
catch(IOException | NullPointerException ex){
ex.printStackTrace();
}
No need to close() resources because Java 7 provides try-with-resources statement
try(FileOutputStream fos = new FileOutputStream("movies.txt");
DataOutputStream dos = new DataOutputStream(fos)) {
dos.writeUTF("Java 7 Block Buster");
} catch(IOException e) {
// log the exception
}
binary literals with prefix “0b” or “0B”

Answer 7

I think ForkJoinPool and related enhancement to Executor Framework is an important addition in Java 7.

Answer 8

The following list contains links to the the enhancements pages in the Java SE 7.
Swing
IO and New IO
Networking
Security
Concurrency Utilities
Rich Internet Applications (RIA)/Deployment
Requesting and Customizing Applet Decoration in Dragg able Applets
Embedding JNLP File in Applet Tag
Deploying without Codebase
Handling Applet Initialization Status with Event Handlers
Java 2D
Java XML – JAXP, JAXB, and JAX-WS
Internationalization
java.lang Package
Multithreaded Custom Class Loaders in Java SE 7
Java Programming Language
Binary Literals
Strings in switch Statements
The try-with-resources Statement
Catching Multiple Exception Types and Rethrowing Exceptions with Improved Type Checking
Underscores in Numeric Literals
Type Inference for Generic Instance Creation
Improved Compiler Warnings and Errors When Using Non-Reifiable Formal Parameters with Varargs Methods
Java Virtual Machine (JVM)
Java Virtual Machine Support for Non-Java Languages
Garbage-First Collector
Java HotSpot Virtual Machine Performance Enhancements
JDBC
Reference 1 Reference 2