The try-with-resource statement

The try-with-resource statement previously required a new variable to be declared for each resource in the statement when a final variable was used. Here is the syntax for the try-with-resource statement prior to Java 9 (in Java 7 or 8):

    try ( // open resources ) 
    {
      // use resources
    } catch (// error) 
    {  // handle exceptions
    }
    // automatically close resources

Here is a code snippet using the preceding syntax:

    try ( Scanner xmlScanner = new Scanner(new File(xmlFile));
    {
       while (xmlScanner.hasNext())
       {
          // read the xml document and perform needed operations
       }
      xmlScanner.close();
    } catch (FileNotFoundException fnfe)
      {
         System.out.println("Your XML file was not found.");
      }

Now, with Java 9, the try-with-resource statement can manage final variables without requiring a new variable declaration. So, we can now rewrite the earlier code, as shown here in Java 9:

    Scanner xmlScanner = new Scanner(newFile(xmlFile));
    try ( while (xmlScanner.hasNext())
    {
       {
         // read the xml document and perform needed operations
       }
       xmlScanner.close();
    } catch (FileNotFoundException fnfe)
      {
         System.out.println("Your XML file was not found.");
      }

As you can see, the xmlScanner object reference is contained inside the try-with-resource statement block, which provides for automatic resource management. The resource will automatically be closed as soon as the try-with-resource statement block is exited.