
Java has been constantly growing so much bigger that I cannot fathom all that is added to it.
Let me sum up the ones I found useful in my daily use. Consider this an introduction to Java 7 and we’ll be rolling out more detailed posts on each topic eventually.
String in switch case:
Let me start with a favourite,
With java 7, we can use string in switch case!
switch(str){ //str of type String
case "abc": //do something
case "efg": //do other thing
}
Multiple Exception Handling:
No need to copy paste many catch expressions. We can bundle related exceptions in a single catch.
try{
get_A_Coffee (); //do someting;
}
catch(NotTastyException, NotHotEnoughException coffeExpObj){ //bundle similar exceptions
throwCoffeAndGetNew(coffeExpObj); //handle
}
Type Inference:
Lists can be put as such easily!
Map<String, Integer> = new HashMap<String, Integer>(); //no need to write like this
Map<String, Integer> = new HashMap<>(); //this will just do
Elvis Operator:
This is from groovy language. ( ?: looks like Elvis)
Instead of x!=null? x: y, we can write as x ?: y
Ex:- Integer ival = (input from user); // may be null
int i = ival ?: -1; // no NullPointerException from unboxing
Module:
We hear something called Module in Java 7, module or a module definition by book is ‘a logical unit of set of files, resources and its dependencies that can be versioned, packaged and deployed in the module repository for re-use by some other application.’ Each module consists of a module meta-data that is self-describing. (Good for JAR versioning). Modules can be exported & imported between projects.
/* module meta-data */
module A @ 1.0 //this module class is of version 1.0
{
requires B @ 2.1; //this needs B of version 2.1
requires C @ 1.1; //this needs C of version 1.1
} /*meta-data end*/
module A;
package com.sample;
public class sample class{
public void sample()
{}
}
Note: If class or one of its members or constructors is declared module, it will be accessible from a type that belongs to the same module.If you don’t get it chill, I didn’t either, at first. We’ll see more on this in following posts.
Whole new I/O API:
The Java team has rolled out a whole new IO package, java.nio(new IO)
Tons of useful things for file and path handling under this.
Path is one such new class. (http://docs.oracle.com/javase/tutorial/essential/io/pathOps.html)
It’s like a Unix path for manipulation, finding file, properties etc
Path searchPath = Paths.get(“c:/sample”);
final Path findFile = Paths.get(“samplefile”);
//similar to FileSystems.getDefault().getPath("/samplefile");
FileVisitor visitor = new SimpleFileVisitor()
{
public FileVisitResult visitFile(Path file, BasicFileAttributes attrs)
{
if(file.getName().startsWith(findFile)
{
//do something
}}
};
Files.walkFileTree(searcPath, visitor);
Other features of nio are Buffers, Channels, Selectors, Character sets, asynchronous I/O, File Notifications, Directory Operations. know moreGarbage First!:
No more chaos with a fuzzy GC,
• All new garbage collector, the “Garbage First Collector”.
• Memory split into multiple regions as opposed to 2 regions in the last version.
• Quite predictable and provides greater through-put for memory intensive applications.
• Performs faster than the last parallel collectors.
There are more features like Fork and Join, Cache API (temporary, permanent), new Date and time API. Stay tuned to pro them too.
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