In Java 9 try-with-resources statement has been improved. Now if you already have final or effectively final resource you can use it in try-with-resources statement without need to declare a dummy variable.

Effectively final is the variable whose value is never changed after assignment.
For example in before Java 9 way of using the try-with-resources statement would be:

try (BufferedReader br = new BufferedReader(new FileReader("file.txt"));) {
  while (br.readLine() != null) {
    System.out.println(br.readLine());
  }
}

In Java 9 the same code could be rewritten like this:

BufferedReader br = new BufferedReader(new FileReader("file.txt"));
try (br) {
  while (br.readLine() != null) {
    System.out.println(br.readLine());
  }
}