Features of Java 7.0

• Support for Strings in Switch
• Improved Type Inference for Generic Instance Creation
• Automatic Resource Management
• Binary integral literals and underscores in numeric literals
• Multi-catch and more precise rethrow

Support for Strings in Switch

import java.util.Scanner;

// switch supports strings 
public class StringSwitch {
    public static void main(String[] args) {
        
          Scanner s= new Scanner(System.in);
          System.out.print("Enter the name of programming language you use : ");
          String lang = s.nextLine();   // read a line from keyboard
          switch(lang) {
              case "java" : 
                  System.out.println("Java Programmer"); break;
              case "c#" : 
                  System.out.println(".Net Programmer"); break;
              case "c++" : 
                  System.out.println("C++ Programmer"); break;
              default:
                  System.out.println("Programmer"); break;
          }
    }
}

Improved Type Inference for Generic Instance Creation

  Map<String, List<String>> anagrams = new HashMap<String, List<String>>();

  Map<String, List<String>> anagrams = new HashMap<>();

Automatic Resource Management

        FileOutputStream fos = new FileOutputStream(path);
        try {
            // code to process fos
        } 
        catch(Exception ex) {
            System.out.println(ex);
        }
        finally {
           fos.close();
        }

       try (FileOutputStream fos = new FileOutputStream(path))
        {
            // code to process fos
        }
        catch(Exception ex) {
            System.out.println(ex);
        }

Binary integral literals and underscores in numeric literals

        int n = 0b10000000;
        System.out.println(n);  // prints 128

        
        int n2 =  121_31_23_232;   // integer literal with underscores 
        int n3 =  0xff_dd;   // hexa literal with underscores 
        System.out.println(n2);
        System.out.println(n3);

Multi-catch and more precise rethrow

         try {
            int v = Integer.parseInt(num);
            int result = 100 / v;
            System.out.println(result);
        }
        catch(NumberFormatException | ArithmeticException ex ) {  // multi-catch 
            System.out.println("Not a valid number or zero");
        }

More precise rethrow

class Ex1 extends Exception { }
class Ex2 extends Exception { }

public class RethrowException {

    public void m1(int v)  throws Ex1 , Ex2 {
        try {
            if (v < 0) {
                throw new Ex1();
            } 
            else
               if ( v > 100 ) {
                   throw new Ex2();
               }
            // process 
        } 
        catch (Exception ex) {
            throw ex;   //   unreported exception java.lang.Exception; must be caught or declared to be thrown
        }
    }
}

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