Java version history from 1.4 to 1.8

1) Java 4 Features :

The important feature of J2SE 4 is assertions. It is used for testing.

• Assertion (Java 4)

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2) Java 5 Features :

The important features of J2SE 5 are generics and assertions. Others are autoboxing, enum, var-args, static import, for-each loop (enhanced for loop etc.

• For-each loop (Java 5)
• Varargs (Java 5)
• Static Import (Java 5)
• Autoboxing and Unboxing (Java 5)
• Enum (Java 5)
• Covariant Return Type (Java 5)
• Annotation (Java 5)
• Generics (Java 5)

Try-with-resources in Java 7

Try-with-resources in Java 7

Try-with-resources in Java 7 is a new exception handling mechanism that makes it easier to correctly close resources that are used within a try-catch block.

Resource Management With Try-Catch-Finally, Old School Style 

Managing resources that need to be explicitly closed is somewhat tedious before Java 7.

private static void printFile() throws IOException {
    InputStream input = null;

    try {
        input = new FileInputStream("file.txt");

        int data = input.read();
        while(data != -1){
            System.out.print((char) data);
            data = input.read();
        }
    } finally {
        if(input != null){
            input.close();
        }
    }
}

The code marked in bold is where the code can throw an Exception. As you can see, that can happen in 3 places inside the try-block, and 1 place inside the finally-block.

The finally block is always executed no matter if an exception is thrown from the try block or not. That means, that the InputStream is closed no matter what happens in the try block. Or, attempted closed that is. TheInputStream's close() method may throw an exception too, if closing it fails.

What's new in Java 7

I have been reading  about Java 1.7. There are articles about what's new,I have read them and compromised to write the language changes with examples.

So the normal developer can understand the changes easily by examples.Here I am mainly focusing on language  changes  I have taken these language changes from wikipedia https://en.wikipedia.org/wiki/Java_version_history#Java_SE_7_.28July_28.2C_2011.29. You can see all other changes here.

Language Changes 

• Strings in switch
• Automatic resource management in try-statement 
• Improved type inference for generic instance creation, aka the diamond operator <>
• Language  Support for Collections.
• Binary integer literals
• Allowing underscores in numeric literals
• Catching multiple exception types and re throwing exceptions with improved type checking

There is a list of other features available on the OpenJDK 7 features page.