New/strange Java “try()” syntax?

Question

While messing around with the custom formatting options in Eclipse, in one of the sample pieces of code, I saw code as follows:

/**
 * \'try-with-resources\'
 */         


        

Answer 1

It was added in Java 7. It's called the try-with-resources statement.

/edit

Might as well throw this in here too. You can use the try-with-resources statement to manage Locks if you use a wrapper class like this:

public class CloseableLock implements Closeable {
    private final Lock lock;

    private CloseableLock(Lock l) {
        lock = l;
    }

    public void close() {
        lock.unlock();
    }

    public static CloseableLock lock(Lock l) {
        l.lock();
        return new CloseableLock(l);
    }
}

try(CloseableLock l = CloseableLock.lock(lock)) { // acquire the lock
    // do something
} // release the lock

However, since you have to declare a variable for every resource, the advantage of this is debatable.

Answer 2

That is called with a try with resources. in a try with resources, any kind of closable stream declared in the resources section will be closed after the try statement is done. So it pretty much is a

try{
InputStream is;
//Stuff
}finally{
is.close()
}