system.out

问题 I noticed that any call to System.out.println() from a JAR file that hasn't been started by the command line (i.e. a Runnable JAR file started by user with double-click) won't open the console. After doing some research, I found multiple answers on the site: System.out.println in jar There is no problem doing like that. But where do you expect to see the output? What happens to “System.out.println()” in executable jar? If you run the code in some way that doesn't attach a console - such as

问题 I have a desktop application, when there is a freeze for some minutes, there is a thread which monitors the freeze and it starts dumping stack traces of all threads(this is done in native call so that JVM_DumpAllStacks can be invoked) into temporary file. Then the temporary file is read as String after the native call and it is used to log in application's own logging framework. The problem is, After all these process, I am not able to restore System.out to CONSOLE stream. This is better

问题 This question already has answers here : System.out is declared as static final and initialized with null? [duplicate] (2 answers) Closed 3 years ago . As to access the methods of PrintStram class an object must be created, so how the out variable is able to access those methods when it is assigned null. public final static PrintStream out = null; This is the declaration in System class. I tried to write the similar code but then it gives NullPointerException. My code is given below. class

来源： https://stackoverflow.com/questions/49604275/formatting-java-strings-with-system-out-printf

来源： https://stackoverflow.com/questions/49604275/formatting-java-strings-with-system-out-printf

问题 I am facing a rather unusual situation. I am using printWriter with System.out to print the bytes from a file onto console, first using a ByteStreamReader and then a CharacterStreamReader . The problem is after the output of ByteStreamReader , subsequent System.out.println statements are not printing anything on console. I tried using flush on System.out.flush() but still not getting output. Code: FileStream fs = new FileStream(); //ByteStreamReader String source = "./test_zh.txt";

问题 I'm learning about I/O and the stream abstraction. I came across this little toy example which should open a stream attached to a text file and display the content (simple ASCII text) to the default destination attached to System.out, the console.. It doesn't display a thing,where am I wrong? import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.IOException; import java.io.InputStream; public class Test { public static void main(String[] args) throws IOException

问题 This question already has answers here : In Java, is the result of the addition of two chars an int or a char? (8 answers) Closed 3 months ago . I have the following code: class Example{ public static void main(String args[]){ System.out.println('1'+'1'); } } Why does it output 98 ? 回答1: In java, every character literal is associated with an ASCII value. You can find all the ASCII values here '1' maps to ASCII value of 49. thus '1' + '1' becomes 49 + 49 which is an integer 98. If you cast

问题 This may be a trivial question but I can't easily find an answer. I've got a simple program in Java: System.setOut(new PrintStream(new File("stdout.txt"))); ... ... ProcessBuilder pb = new ProcessBuilder("... some args ..."); pb.inheritIO(); pb.start().waitFor(); My intention is to store all output of the process (including child pb ) in the stdout.txt . But, this seem not to work and the output of pb is redirected to my process parent's standard output as if System.setOut(...) was never

问题 We all mostly use System.out.println in the Console of our IDE. I am using Eclipse. I can also clearly see the println() message on my Mac's Console app. Which is nice for my personal things. And here is the code: public class Main { public static void main(String[] args) { System.out.println("Is this logged anywhere?"); } } And here's what I see on my Mac: Does Windows have something similar to the Mac's version of Console? 回答1: Sadly, as previously said, we don't really have that on Windows