IntelliJ Idea debug/run console; System.out.flush not flushing - java

This has been bugging me for the last couple days, because it used to work. I upgraded my intellij and now it doesn't work. I don't want to go back, but I need an answer.
So, I'm writing a console application, and while it runs, I want to have a shell'd out display of progress. It works fine when it's running, but when I'm debugging in IntelliJ Idea, the System.out.flush() won't flush to the console unless the buffer contains a newline. I wrote the following unit test to find out if it was me or my application.
#Test
public void flushTest() {
int loops = 100;
for (int i = 0 ; i < 100 ; ++i) {
System.out.print("This is a print, does it flush : " + i + "\r");
if (i %10 == 0) {
System.out.print("\n");
}
System.out.flush();
}
}
Spoiler, it is the application. I don't know what's changed, but it makes it very difficult to debug display issues without doing a full build and running on the command line. If someone can help me figure out why this changed and/or help me fix it so It'll flush properly, I'd be very grateful.

Tested on version 2016.3.5, the problem is still there.
The bug is caused by all characters after "\r" will be cleared in the console.
For example, using a string "Test\r" will be got "Test" written to console, after cursor is moved to the left by the "\r", all the characters "Test" is cleared. So you won't see anything.
The workaround is to move "\r" to the beginning of the string. For example, "\rTest" will see the output in console.
The following codes will illustrate the bug. You will see "0000" and "111" will appear for 1 second and then all are cleared by "22".
System.out.print("0000\r");
Thread.sleep(1000);
System.out.print("111\r");
Thread.sleep(1000);
System.out.print("22\r");

Until this issue is not resolved, current workaround is to use
-Deditable.java.test.console=true (specify it in idea.properties).

Related

Java - IF statement treats value as NULL even though it isn't when checking in debug

This is a strange one so any help would be appreciated.
I'm working on a Spring Batch job that sends transactions to a Kafka topic and when successful the status code is returned as a String: "C". There's a check for if this status code is null and if so it will give an appropriate error message as below to be outputted onto a table later on.
if (kafkaWriter.getKafkaStatusCode() == null)
{
messagingResultCode = CommonConstants.KAFKA_NULL_RESULT;
}
So what's happening is that for several transactions that are picked up by the job I get a Kafka null result error message because of the above code so I went into debug to see what was happening putting a breakpoint at where messagingResultCode is set.
But when I evaluated "kafkaWriter.getKafkaStatusCode() == null" it showed as "(boolean) false" in Spring Tools Suite. When looking at the KafkaStatusCode it shows as "C" so definitely not null, but it still went into the code anyway.
All getKafkaStatusCode() does is return a String:
public String getKafkaStatusCode() {
return kafkaStatusCode;
}
This only ever happens on the first job that's been run on the server (I'm using Liberty) and on all subsequent runs the code behaves as expected.
I've tried initialising the String messagingResultCode to null, "" and a default value but the same thing happens every time.
Thanks
".or: (time/) asynchronity is in place ;) (I.e. debugging influences the outcome;) – xerx593 3 hours ago"
#xerx593 You were right, the debugger wasn't showing me the correct value which I found after putting in some extra logging and running it in non-debug.
Turns out you can't trust the debugger all the time :)
Thanks

gdx-ai: how to disable behaviour

From yesterday I was looking for a way to disable some behaviour in Gdx-Ai, I wrote code like this:
arriveSteeringBehaviour = new Arrive<Vector3>(character, MainCharacter.getTarget()) //
.setTimeToTarget(0.1f)
.setArrivalTolerance(0.0002f)
.setDecelerationRadius(8);
arriveSteeringBehaviour.setEnabled(true);
character.setSteeringBehavior(arriveSteeringBehaviour);
when "Arrive Distance" <= "Deceleration Radius" I'm trying to disable the Arrive Behaviour like this
if (arriveSteeringBehaviour.getDistance() <= arriveSteeringBehaviour.getDecelerationRadius() ) {
arriveSteeringBehaviour.setEnabled(false);
character.setSteeringBehavior(null);
}
but it's doesn't worked, character object still moving around, anyone can figure this out? thanks
note: in update method, I did disable any translation also disabled character.update(GdxAI.getTimepiece().getDeltaTime()); line.

The method sign.setline is not working

im haveing a problem running a setline command
witch i want to set the line of a sign with..
it isn't doing anything
This is the part of the code that has the setline method in it it will run with a few other things when the player will give the input (the "if (SignEvent.isNumericArray(times))" is true for sure and the code is running i did check that )
if (SignEvent.isNumericArray(times)){
double uses = Double.parseDouble(times);
uses = uses -1;
sign.setLine(2 , uses + "/" + str[1] + parts[1]);
if (uses <= 0){
sign.setLine(0, ChatColor.STRIKETHROUGH + "StartPayment");
}
}
i did check a few things :
no errors in console or eclipse error list
object sign is type Sign imported from import org.bukkit.block.Sign
object sign is the right sign (checked by doing e.getPlayer().sendMessage(sign.getLine(0)); it worked..
no matter what the string is it isn't working
no matter where i put this line of code its not working
the this line is running
i just have no idea what could i do to fix it i tried a lot of things and im pretty sure the problem is in the
sign.setLine(2 , uses + "/" + str[1] + parts[1]); line
any one have any idea for what did i do wrong ?
Note: no matter where in this method i put the setline method or with what string/lineIndex ,it isn't doing anything
I think you have to execute sign.update(); after a modification to apply changes.

Eclipse debugger "jumps" skipping important code

I have a weird problem debugging an android application.
To be accurate, I copy here the exact code I'm running on:
// Get the puzzles from cache
List<PuzzleDetails> newPuzzles = m_cachedPuzzles.getPuzzles(count);
if(newPuzzles.size() > 0){
// Remove from cache
m_cachedPuzzles.removePuzzles(newPuzzles); // LINE (A)
// Add the new puzzles from cache immediately
m_ownedPuzzles.addPuzzles(newPuzzles);
Log.d("requests", "" + newPuzzles.size() + " moved from cache to user");
}
int left = count - newPuzzles.size();
String deviceId = ResourcesPublisher.getInstance().getDeviceId();
// Don't let anyone else use these points for now
ChallengePointsManagerImpl.getInstance().usePoints(left);
Log.d("requests", "aquirePuzzles(" + left + ")");
// Get a list of requests for 'left' number of puzzles
RequestList reqList = getRequestList(left);
// TODO this is a bug, now
if(reqList.size() > 1){
reqList = getRequestList(left); // LINE (B)
}
When I run on this code, after stepping over the line (A)
m_cachedPuzzles.removePuzzles(newPuzzles);
The debugger "jumps" to the last line (B)
reqList = getRequestList(left);
A simple check shows it really skipped all code between these code lines.
For example the Log.d(...) was never called nor written.
Can anyone give me a clue why does it happen???
Thanks!
Try to do a right click > refresh on the project as it appears on the Project Explorer after you compile the code and before you start debugging.
Perhaps an exception was thrown from line A, and the next step corresponds to it closing off this stack frame?
mIsReaded = (mIsReaded)?false:true;
//mIsReaded = !mIsReaded;
saveReadFlag();
refreshUI();
Toast.makeText(getSherlockActivity(),...
In my case commented codeline cause the similar problem (two lines are skipped). For to solve it I just changed this line by codeline posted above (I mean mIsReaded = (mIsReaded)?false:true;) So different cases haves different solutions. It is result of code optimization by compiler, so please refactor something in (inside)
m_cachedPuzzles.removePuzzles(newPuzzles);
I had the same problem. The thing is, you are probably debugging the code that is in your IDE and not the on on the server. You have to deploy the code from the IDE (Eclypse, Netbeans etc.) on the server. It worked for me! Good luck!
Not directly related to Eclipse but I experienced a similar problem using the Xamarin Extension for Visual Studio and my realization may be of some help. I was developing an App with a Class library. when i made changes to the library then began emulating my App, the DLL wouldn't always rebuild so the debugger would step through the PDB as it was before my latest changes. After rebuilding the DLL, it would step through fine.
In short, rebuild dependencies if there are any changes made.
Hope you solve your issue. Have a good one
comment TODO using multi-line comment
/*// TODO this is a bug, now*/
and try again.

Program output lost when passed through PsExec

(This is a question my coworker posted elsewhere, but I thought I'd post it here to see if I could hit a different audience.)
Hello all,
I'm testing the possibility of writing a small java application the will use Psexec to kick off remote jobs. In the course of testing binding the stdin and stdout of a java program to psexec I came across an odd bug.
My test program is a basic echo program. It starts a thread to read from stdin and then pipes the read output directly back to stdout. When run on the local machine, not from psexec, it works beautifully. Exactly as it should.
However, when I call it from PsExec the first time the input is piped directly into stdout it is lost. What makes the bug really bizzare is that it is only the first time the input is piped directly into stdout that it is lost. If the input String is appended to another string it works fine. Either a String literal or a String variable. However, if the input String is sent directly to stdout it doesn't go through. The second time it is sent to stdout it goes through fine - and everytime there after.
I'm at a complete loss as to what's going on here. I've tried to test for every possible bug I can think of. I'm out of ideas. Did I miss one or is this just something inside psexec?
Here is the code in question, it's in three classes (one of which implements an interface which is a single function interace).
The Main class:
public class Main {
public static void main(String[] args) {
System.out.println("Starting up.");
CReader input = new CReader(new BufferedReader(
new InputStreamReader(System.in)));
CEcho echo = new CEcho();
input.addInputStreamListener(echo);
input.start();
System.out.println("Successfully started up. Awaiting input.");
}
}
The CReader class which is the thread that reads from stdin:
public class CReader extends Thread {
private ArrayList<InputStreamListener> listeners =
new ArrayList<InputStreamListener>();
private boolean exit = false;
private Reader in;
public CReader(Reader in) {
this.in = in;
}
public void addInputStreamListener(InputStreamListener listener) {
listeners.add(listener);
}
public void fireInputRecieved(String input) {
if(input.equals("quit"))
exit = true;
System.out.println("Input string has made it to fireInputRecieved: "
+ input);
for(int index = 0; index < listeners.size(); index++)
listeners.get(index).inputRecieved(input);
}
#Override
public void run() {
StringBuilder sb = new StringBuilder();
int current = 0, last = 0;
while (!exit) {
try {
current = in.read();
}
catch (IOException e) {
System.out.println("Encountered IOException.");
}
if (current == -1) {
break;
}
else if (current == (int) '\r') {
if(sb.toString().length() == 0) {
// Extra \r, don't return empty string.
continue;
}
fireInputRecieved(new String(sb.toString()));
sb = new StringBuilder();
}
else if(current == (int) '\n') {
if(sb.toString().length() == 0) {
// Extra \n, don't return empty string.
continue;
}
fireInputRecieved(new String(sb.toString()));
sb = new StringBuilder();
}
else {
System.out.println("Recieved character: " + (char)current);
sb.append((char) current);
last = current;
}
}
}
}
The CEcho class, which is the class that pipes it back to stdout:
public class CEcho implements InputStreamListener {
public void inputRecieved(String input) {
System.out.println("\n\nSTART INPUT RECIEVED");
System.out.println("The input that has been recieved is: "+input);
System.out.println("It is a String, that has been copied from a " +
"StringBuilder's toString().");
System.out.println("Outputting it cleanly to standard out: ");
System.out.println(input);
System.out.println("Outputting it cleanly to standard out again: ");
System.out.println(input);
System.out.println("Finished example outputs of input: "+input);
System.out.println("END INPUT RECIEVED\n\n");
}
}
And finally, here is the program output:
>psexec \\remotecomputer "C:\Program Files\Java\jre1.6.0_05\bin\java.exe" -jar "C:\Documents and Settings\testProram.jar"
PsExec v1.96 - Execute processes remotely
Copyright (C) 2001-2009 Mark Russinovich
Sysinternals - www.sysinternals.com
Starting up.
Successfully started up. Awaiting input.
Test
Recieved character: T
Recieved character: e
Recieved character: s
Recieved character: t
Input string has made it to fireInputRecieved: Test
START INPUT RECIEVED
The input that has been recieved is: Test
It is a String, that has been copied from a StringBuilder's toString().
Outputting it cleanly to standard out:
Outputting it cleanly to standard out again:
Test
Finished example outputs of input: Test
END INPUT RECIEVED
have you tried redirecting the output into a file ( java... >c:\output.txt )? this way you could doublecheck if everything is going into stdout and maybe just getting eaten by psexec
PsExec is eating the output. Next interesting thing might be where it's eating the output. You could check this by getting a copy of Wireshark and checking whether the output in question is traversing the network or not. If it's not, then it's being eaten on the remote side. If it is, it's being eaten locally.
Not that I'm really sure where to go from there, but collecting more information certainly seems like a good path to be following...
I was having the same issue and tried multiple combinations of redirects.
This is what worked:
processBuilder.redirectErrorStream(true);
processBuilder.redirectOutput(Redirect.PIPE);
processBuilder.redirectInput(Redirect.INHERIT);
final Process process = processBuilder.start();
// Using Apache Commons IOUtils to get output in String
StringWriter writer = new StringWriter();
IOUtils.copy(process.getInputStream(), writer, StandardCharsets.UTF_8);
String result = writer.toString();
logger.info(result);
final int exitStatus = process.waitFor();
The Redirect.INHERIT for processBuilder.redirectInput got me the missing remote command output.
Is System.out not configured for autoflush? After the first print try System.out.flush() and see if the first line appears without more lines being printed.
(oh yeah, seriously, it is "RECEIVED", not "RECIEVED".)
OK, I've been thinking about this over the weekend and I since you are jumping from machine to machine I wonder if maybe there is a CharSet issue? Maybe it is eating the string the first time and dealing with a different code page or character set issue? Java is 16bit characters normally and windows is either 8bit with code pages or utf-8 these days.
Any chance the local and remote machines have different default character sets? If you are sending localized data over the net it might misbehave.
What I see when running psexec is that it spawns a child window to do the work but doesnt return that program's output to it's console window. I would suggest using WMI or some form of windows process API framework to gain a level of control you appear to lack with psexec. Surely java has an equivalent to .Net's System.Diagnotics.Process class.
Maybe you could try passing a copy of input to your listeners:
public void fireInputRecieved(String input) {
if(input.equals("quit"))
exit = true;
String inputCopy = new String(input);
System.out.println("Input string has made it to fireInputRecieved: "
+ input);
for(int index = 0; index < listeners.size(); index++)
listeners.get(index).inputRecieved(inputCopy);
}
I had similar problems with listeners where a passed variable would end up empty unless I did pass an explicit copy of it.
I don't necessarily have an answer, but some comments may prove helpful.
The "pass a copy" idea shouldn't matter, since your output successfully prints the string twice before the failure, then succeeds again afterward.
auto-flush shouldn't matter either, as you've already mentioned
Niko's suggestion has some merit, for diagnostic purposes. Mixed with Mark's suggestion, it makes me wonder if there aren't some invisible control characters getting involved somewhere. What if you printed the characters byte values as a diagnostic step?
You know that the value is "Test" (at least in the output you gave us). What happens if you pass "Test" directly to the failing printLn statement?
In situations like this, you want to gain as much information as possible. Insert breakpoints and analyze characters. Send the bytes to files and open them in hex editors. Do whatever you can to trace things as accurately and as precisely as possible.
Come up with weird test scenarios and try them, even if they shouldn't possibly help. You never know what good idea you might have while analyzing the results of the hopeless idea.
I'd guess that there is a bogus byte in there prefacing the T. According to JavaDocs, an InputStreamReader will read one or more bytes, and decode them into characters.
You could have an escape sequence or spurious byte in there, masquerading as a multibyte character.
Quick check - see if "current" is ever > 128 or < 33.
What if you used a CharArrayReader to get individual bytes, without any charset translation?
The theory is that during the first attempt to output the String using println, it's sending an escape character of some sort, eating the rest of the string. During later prints, either Java or the network pipe are handling or removing it, since it previously got that escape sequence, perhaps changing the handling in some way.
As an unrelated nit, sb.toString() returns a new String, so it's unnecessary to call "new String(sb.toString())"
Same issue here, I'm going through this post again and again these days, hoping I can find some solution. Then I decide I should give up psexec and find some alternative. So this is the thing: PAExec. Works perfect for getting command output.
How are you executing PsExec? My suspicion is that this is some code within PsExec which is actually doing echo suppression, possibly for the purposes of protecting a password. One way to test this hypothesis would be to change this code:
System.out.println("Outputting it cleanly to standard out: ");
System.out.println(input);
System.out.println("Outputting it cleanly to standard out again: ");
System.out.println(input);
to this:
System.out.println("Outputting it cleanly to standard out: ");
System.out.print(' ');
System.out.println(input);
System.out.println("Outputting it cleanly to standard out again: ");
System.out.println(input);
...thereby causing the output to be (if I'm right):
Outputting it cleanly to standard out:
Test
Outputting it cleanly to standard out again:
Test
Finished example outputs of input: Test
In particular, it's noticeable that the apparently-suppressed line is the first line which consists solely of Test - which is exactly the text you've just sent to the remote system. This sounds like PsExec attempting to suppress a remote system which is echoing its input in addition to producing its own output.
Is the password of the user on the remote machine perhaps Test? Are you using PsExec's -p parameter? Are you specifying -i?
I am dealing with this same issue and I am wondering if it has to do with how the cmd window and pipes in windows work while you don't have a true windowed session. The suppressed output happens when any new process is spawned. You would think that if you spawn a process that the stdout/stderr/stdin would be inherited from the process that spawned it; after all that is what happens if you spawn the process from a normal cmd window and the output from the new process is piped back to your own console. However if somewhere in the inheritance of the pipes something were to go wrong, like say not passing a WINDOW.GUI object because there is no physical window, windows doesn't let the stdin/stdout/stdin to be inherited. Can any one do some investigation or open a windows support ticket for this?
Seems no easy solution. My work-around in a recent project is using paexec.exe product. It captures output/error easily in JAVA(java-8), but hangs up upon completion of the remote command execution. When running this inside a server on the hosted machine, I have to spurn a new child JVM process to run paexec.exe and force kill it via its PID upon completion in order to release all the resources.
If anyone has better solution, please post it.

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