try-with-resources

问题 Break doesn't work in try with resources, but work in try without resources! This is a simple example for this situation. I caught this "bug" in work project. When I use try without resources try { Resources resources = getResources() // some code here, look below } I have only one iteration of my cycle, and it's right because I have the condition "if true then break", but when I changed try without recourse on try WITH resources. try (Resources resources = getResources()) { // some code here

问题 As an exercise for school I wrote a method in Java that searches for a character in a file. Here is the code: public static void countLetter(char needle, String hayStack) throws IOException { File f = new File(hayStack); try (Scanner in = new Scanner(f)) { String str = null; while (in.hasNext()){ str += in.next(); } char[] charArr = str.toCharArray(); int counter = 0; for (char c: charArr) { if (c == needle){ counter++; } } System.out.println(counter); } } This does what I need it to but I

问题 I want to write a simple server that listens on a port and spawns new threads for handling new connections. I attempted to use try-with-resources for accepting new connections but failed because sockets in child threads seem to be closed immediately and I don't understand why. Here are 2 simplified examples. a) The working example of the server (without try-with-resources): package MyTest; import java.io.BufferedReader; import java.io.IOException; import java.io.OutputStreamWriter; import

问题 Alright, so I was just writing a quick class and I tried to use the try with resources instead of the try-catch-finally (hate doing that) method and I keep getting the error "Illegal start of type". I then turned to The Java Tutorials section on it: http://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html and it showed that you can assign a new variable in the parenthesis. I'm not sure what is going on. private static final class EncryptedWriter { private final Path

问题 The reader should be closed when a Stream is used in a try-with-resources. Given this: try(Stream<String> lines = new BufferedReader(reader).lines()) { return lines.map(it -> trim ? it.trim() : it) .collect(Collectors.toList()); } ... the reader is not being closed?? This test fails: AtomicBoolean closed = new AtomicBoolean(false); Reader r = new StringReader(" Line1 \n Line2") { @Override public void close() { super.close(); closed.set(true); } }; try(Stream<String> lines = new

问题 The following code uses the try-with-resources construction introduced in Java 8. The occasionallyThrow() method is declared to throw an OccasionalException , the Resource 's close() method to throw a CloseException . Eclipse (Version: Neon Release (4.6.0), Build id: 20160613-1800) adds a warning on the line marked with // dead code that the branch is dead code. Implicitly, Eclipse affirms that the line marked with // alive code is not dead code. Object tryWithResources() throws

问题 In Scala application, am trying to read lines from a file using java nio try-with-resource construct. Scala version 2.11.8 Java version 1.8 try(Stream<String> stream = Files.lines(Paths.get("somefile.txt"))){ stream.forEach(System.out::println); // will do business process here }catch (IOException e) { e.printStackTrace(); // will handle failure case here } But the compiler throws error like ◾not found: value stream ◾A try without a catch or finally is equivalent to putting its body in a

问题 I was reading this link for try-with-resources and it says: The close method of the Closeable interface throws exceptions of type IOException while the close method of the AutoCloseable interface throws exceptions of type Exception . But why? The close method of AutoCloseable could have also thrown IOException is there any example that support that close method of AutoCloseable must throw exceptions of type Exception 回答1: The AutoClosable interface is located in java.lang and is intended to

问题 I have two versions of Java code that gets user input until user types "q" Version 1: public class Test { public static void main(String[] args) { String input = ""; while (!input.equals("q")) { Scanner scanner = new Scanner(System.in); System.out.print("Input: "); input = scanner.nextLine(); System.out.println("Input was: " + input); } } } Version 2: public class Test { public static void main(String[] args) { String input = ""; while (!input.equals("q")) { try(Scanner scanner = new Scanner

问题 I've read this topic, and this blog article about try with resources locks, as the question popped in my head. But actually, what I'd rather like would be a try with lock , I mean without lock instantiation. It would release us from the verbose lock.lock(); try { //Do some synchronized actions throwing Exception } finally { //unlock even if Exception is thrown lock.unlock(); } Would rather look like : ? implements Unlockable lock ; ... try(lock) //implicitly calls lock.lock() { //Do some