该Properties.load将关闭InputStream吗？

Question

I saw this example , and I didn't see the close() method invoked on the InputStream , so would prop.load() close the stream automatically? Or is there a bug in the example?

Answer 1

The Stream is not closed after Properties.load ()

public static void main(String[] args) throws IOException {

    InputStream in = new FileInputStream(new File("abc.properties"));

    new Properties().load(in);

    System.out.println(in.read());
}

The above code returns "-1" so the stream is not closed. Otherwise it should have thrown java.io.IOException: Stream Closed

Answer 2

Why do you ask when the javadoc of Properties.load(InputStream inStream) says this?

The specified stream remains open after this method returns.

It has been saying that since Java 6.

As EJP said in a comment : Don't rely on arbitrary Internet junk. Use the official Oracle Java documentation as your primary source of information.

Answer 3

If you are on Java 7 or later, you can use try-with-resources . Article by Oracle here: http://www.oracle.com/technetwork/articles/java/trywithresources-401775.html .

Any resource declared within a try block opening will be closed. Hence, the new construct shields you from having to pair try blocks with corresponding finally blocks that are dedicated to proper resource management.

The following will close the InputStream automatically (you can add catch and finally , if you need them):

try (InputStream is = new FileInputStream("properties.txt")) {
    // is will be closed automatically
}