How to use try-with-resources for java.util.logging.FileHandler?

I'm having below code and creating log file using java.util.logging.FileHandler.

In this scenario, I should manually close the resources in finally block.

try {
fh = new FileHandler("Test.log");
logger.addHandler(fh);
...
} catch (IOException e) {
e.printStackTrace();
} finally {
  if(fh!=null) { fh.close() };
}

This code works. Now, I thought that it may implement Autocloseable interface. So, I decided to use try-with-resources for FileHandler so that the resources will be automatically closed (to remove manual job of closing the resources).

The code I tried is given below :

try(fh = new FileHandler("Test.log")) {
logger.addHandler(fh);
...
} catch (IOException e) {
e.printStackTrace();
}

But this code doesn't work.

It give an error saying that :

The resource type FileHandler does not implement java.lang.AutoCloseable'

How to close the file handler automatically using try-with-resources if possible ?
Do I need to close manually ? Or there is any other approach that I can take.

Solution

Firstly, FileHandler class doesn't implement AutoCloseable interface.

So, you can't use try-with-resources on FileHandler.

Therefore, you have to call the close() method explicitly.

So, you have to go for the first approach you took.

public class Example {

    private static Logger logger = Logger.getLogger("...");

    public static void main(String[] args) {
        FileHandler fh = null;
        try {
            fh = new FileHandler("Test.log");
            logger.addHandler(fh);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (fh != null) {
                fh.close();
            }
        }
    }

}

You can try creating your own custom Filehandler class and implement AutoCloseable interface in that.

For example :

class CustomFileHandler implements AutoCloseable {

    private FileHandler fileHandler;

    public CustomFileHandler(FileHandler fileHandler) {
        this.setFileHandler(fileHandler);
    }

    @Override
    public void close() throws Exception {
        if (fileHandler != null) {
            fileHandler.close();
        }
    }

    public FileHandler getFileHandler() {
        return fileHandler;
    }

    private void setFileHandler(FileHandler fileHandler) {
        this.fileHandler = fileHandler;
    }

}

public class Example {

  private static Logger logger = Logger.getLogger("...");

  public static void main(String[] args) {
    try (CustomFileHandler fh = new CustomFileHandler(new FileHandler("Test.log"))) {
        logger.addHandler(fh.getFileHandler());
        ........
    } catch (Exception e) {
        e.printStackTrace();
    } 
  }

}