system.out

问题 I have a java application that takes input via a Scanner reading System.in, and gives output via System.out. The scanner is always active, it does not terminate without using Ctrl+C via the terminal or ending the process in an IDE. I'm running into some behavior that leads me to believe System.out is not flushing properly. In my code there are the lines: System.out.print(",\\" + '\n'); System.out.print(" " + someString); (someString does not contain a newline character) When I execute this

问题 I have a java application that takes input via a Scanner reading System.in, and gives output via System.out. The scanner is always active, it does not terminate without using Ctrl+C via the terminal or ending the process in an IDE. I'm running into some behavior that leads me to believe System.out is not flushing properly. In my code there are the lines: System.out.print(",\\" + '\n'); System.out.print(" " + someString); (someString does not contain a newline character) When I execute this

问题 I am just a newbie in Java. I was wondering the way System.out.println() is used. Out is a static field inside System class. The type of out is PrintStream . But when I saw the constructor of PrintStream class, it takes a parameter of type OutputStream and as far as I know we cannot create the object of an abstract class. In that case we must pass some subclass's object to the constructor of PrintStream . What is that class? Same is the System.in . It is also InputStream 's reference but what

问题 I overheard an argument about System.out.print() today. One person claimed that since print() doesn't including the terminating \n , the buffer it writes to will eventually fill up and start losing data. The other person claimed that they had been using System.out.print() for all their Java programs and had never run into this issue. Is the first person right? Is it possible for System.out.print() to start blocking or dropping data if stdout is full? Is there an example of code that will

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: What's the meaning of System.out.println in Java? I was looking for the answer of what System , out and println are in System.out.println() in the Java. I searched and found a different answer like these: System is a built-in class present in java.lang package. This class has a final modifier, which means that, it cannot be inherited by other classes. It contains pre-defined methods and fields, which provides

问题 This question already has answers here : Java: System.out.println and System.err.println out of order (7 answers) Closed 6 years ago . Please consider this java code: public class CMain { public static void main(String[] args){ for (int i = 0; i < 10; i++) { System.out.println("A"); System.err.println("B"); } } } By a quick look at the code, some of us may think the output has to be the print of As and Bs alternatively. However is not! It is a random appearance of 10 A characters and 10 B

问题 I am reading Java Concurrency in Practice, according to some java code in it, System.out.println() will led to ConcurrentModificationException . The code is below : private final Set<Integer> set = new HashSet<Integer>(); public synchronized void add(Integer i) {set.add(i); } public synchronized void remove(Integer i) {set.remove(i);} public void addTenThings() { Random r = new Random(); for (int i = 0; i < 10; i++) { add(r.nextInt()); } System.out.println("DEBUG: add ten elements to " + set

问题 This might be a very dumb question but, is there a way to fire a trigger whenever something is printed to the console in Java and listen for it somewhere else? I have very little understanding of triggers or of the System class (or of Logger for that matter) so if there is an easier way of doing this (without triggers) please tell me so. We are trying to use Logger to log all of our tests. Currently, we have been using the simple "System.out.println" to log everything in the console, so I was

问题 System.out is a PrintStream object. I read the documentation on PrintStream. What I don't get is why System.out.print causes the buffer to be flushed? Shouldn't that happen only for println? 回答1: Shouldn't that happen only for println? The Javadoc doesn't say when it won't be flushed. And it says it will be flushed on a println() or a newline . 回答2: At the risk of repeating the facts that have already been noted, let me try to interpret the doc a little differently... It seems that it's only

问题 I have a byte array which looks like this: [0, 0, 0, 0, 0, 0, 0, 0, 122, 98, 117, 54, 46, 0, 0, 115, 122, 42, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 116, 121, 116, 117, 108, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 32, 107, 111, 98, 105, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,