What is the correct way to silently close InputStream in finally block without losing the original exception?

Question

I am wondering if the below code closes InputStream in finally block correctly

InputStream is = new FileInputStream("test"); try {     for(;;) {         int b = is.read();         ...     } } finally {     try {         is.close();     } catch(IOException e) {     } } 

If an exception happens during is.read() will be it ignored / suppressed if an exception happens during is.close()?

Answer 1

Best way is to use Java 7 and use try with resources, or do same thing manualy and add exception from closing as suppressed exception.

Pre Java 7: If you are throwing your custom exception, you can add in it supressed exception like it is done in Java 7 (in your exception create fields List suppressed and put there exceptions from close operation and when dealing with your exception, look there too. If you cannot do that, I don't know anything better than just log it.

examples: from Java tutorials

static String readFirstLineFromFile(String path) throws IOException {     try (BufferedReader br = new BufferedReader(new FileReader(path))) {         return br.readLine();     } } 

but better form is:

static String readFirstLineFromFile(String path) throws IOException {     try (FileReader fr = new FileReader(path);          BufferedReader br = new BufferedReader(fr)) {         return br.readLine();     } } 

This way even if creation of FileReader is succesfull but creation of BufferedReader fails (eg not enough memory), FileReader will be closed.