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What am I missing? NumberFormatException error

I want to read from a txt file which contains just numbers. Such file is in UTF-8, and the numbers are separated only by new lines (no spaces or any other things) just that. Whenever i call Integer.valueOf(myString), i get the exception.
This exception is really strange, because if i create a predefined string, such as "56\n", and use .trim(), it works perfectly. But in my code, not only that is not the case, but the exception texts says that what it couldn't convert was "54856". I have tried to introduce a new line there, and then the error text says it couldn't convert "54856
"
With that out of the question, what am I missing?
File ficheroEntrada = new File("C:\\in.txt");
FileReader entrada =new FileReader(ficheroEntrada);
BufferedReader input = new BufferedReader(entrada);
String s = input.readLine();
System.out.println(s);
Integer in;
in = Integer.valueOf(s.trim());
System.out.println(in);
The exception text reads as follows:
Exception in thread "main" java.lang.NumberFormatException: For input string: "54856"
at java.base/java.lang.NumberFormatException.forInputString(NumberFormatException.java:68)
at java.base/java.lang.Integer.parseInt(Integer.java:658)
at java.base/java.lang.Integer.valueOf(Integer.java:989)
at Quicksort.main(Quicksort.java:170)
The file in.txt consists of:
54856
896
54
53
2
5634

Well, aparently it had to do with Windows and those \r that it uses... I just tried executing it on a Linux VM and it worked. Thanks to everyone that answered!!

Try reading the file with Scanner class has use it's hasNextInt() method to identify what you are reading is Integer or not. This will help you find out what String/character is causing the issue
public static void main(String[] args) throws Exception {
File ficheroEntrada = new File(
"C:\\in.txt");
Scanner scan = new Scanner(ficheroEntrada);
while (scan.hasNext()) {
if (scan.hasNextInt()) {
System.out.println("found integer" + scan.nextInt());
} else {
System.out.println("not integer" + scan.next());
}
}
}

If you want to ensure parsability of a string, you could use a Pattern and Regex that.
Pattern intPattern = Pattern.compile("\\-?\\d+");
Matcher matcher = intPattern.matcher(input);
if (matcher.find()) {
int value = Integer.parseInt(matcher.group(0));
// ... do something with the result.
} else {
// ... handle unparsable line.
}
This pattern allows any numbers and optionally a minus before (without whitespace). It should definetly parse, unless it is too long. I don't know how it handles that, but your example seems to contain mostly short integers, so this should not matter.

Most probably you have a leading/trailing whitespaces in your input, something like:
String s = " 5436";
System.out.println(s);
Integer in;
in = Integer.valueOf(s.trim());
System.out.println(in);
Use trim() on string to get rid of it.
UPDATE 2:
If your file contains something like:
54856\n
896
54\n
53
2\n
5634
then use following code for it:
....your code
FileReader enter = new FileReader(file);
BufferedReader input = new BufferedReader(enter);
String currentLine;
while ((currentLine = input.readLine()) != null) {
Integer in;
//get rid of non-numbers
in = Integer.valueOf(currentLine.replaceAll("\\D+",""));
System.out.println(in);
...your code

Scanner difficulties with different escape characters

First off let me start by saying that I know I'm not the only one who has experienced this issue and I spent the last couple of hours to research how to fix it. Sadly, I can't get my scanner to work. I'm new to java so I don't understand more complicated explanations that some answers have in different questions.
Here is a rundown:
I'm trying to read out of a file which contains escape characters of cards. Here is a short version: (Numbers 2 and 3 of 4 different card faces)
\u26602,2
\u26652,2
\u26662,2
\u26632,2
\u26603,3
\u26653,3
\u26663,3
\u26633,3
This is the format: (suit)(face),(value). an example:
\u2663 = suit
3 = face
3 = value
This is the code I'm using for reading it:
File file = new File("Cards.txt");
try {
Scanner scanner = new Scanner(file);
while (scanner.hasNextLine()) {
String line = scanner.nextLine();
String[] temp = line.split(",");
cards.add(new Card(temp[0], Integer.parseInt(temp[1])));
}
scanner.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
}
the ArrayList cards should have 52 cards after this containing a name (suit and face) and a value. When i try to print the name this is the output:
\u26633
While it should be:
♣3
Can anyone give me pointers towards a solution? I really need this issue resolved. I don't want you to write my code for me.
Thanks in advance

Simply store directly the suit characters into your files Cards.txt using UTF-8 as character encoding instead of the corresponding unicode character format that is only understood by java such that when it is read from your file it is read as the String "\u2660" not as the corresponding unicode character.
Its content would then be something like:
♠2,2
...
Another way could be to use StringEscapeUtils.unescapeJava(String input) to unescape your unicode character.
The code change would then be:
cards.add(new Card(StringEscapeUtils.unescapeJava(temp[0]), Integer.parseInt(temp[1])));

You'll have to save your file with UTF-8 encoding and then read the file using the same encoding.
♥,1
♥,2
♥,3
Here is the code snippet:
BufferedReader buff = new BufferedReader(new InputStreamReader(
new FileInputStream("Cards.txt"), "UTF-8"));
String input = null;
while (null != (input = buff.readLine())) {
System.out.println(input);
String[] temp = input.split(",");
cards.add(new Card(temp[0], Integer.parseInt(temp[1])));
}
buff.close();
Also, you need to make sure that your console is enabled to support UTF-8. Look at this answer to read more about it.

Reading From File With Comma Delimeter Error

Here's the .txt file i'm trying to read from
20,Dan,09/05/1990,3,Here
5,Danezo,04/09/1990,99,There
And here's how I'm doing it.. Whenever the .txt file has only one line, it seems to be reading from file fine. Whenever more than one line is being read, I get this error
Exception in thread "main" java.lang.NumberFormatException: For input string: "Danezo"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:580)
at java.lang.Integer.parseInt(Integer.java:615)
at AttackMonitor.readFromFile(AttackMonitor.java:137)
at AttackMonitor.monitor(AttackMonitor.java:57)
at MonsterAttackDriver.main(MonsterAttackDriver.java:14)
Java Result: 1
Here's the readfromfile code.
private void readFromFile() throws FileNotFoundException, IOException
{
monsterAttacks.clear();
Scanner read = new Scanner(new File("Attacks.txt"));
read.useDelimiter(",");
String fullDateIn = "";
int attackIdIn = 0;
int attackVictimsIn = 0;
String monsterNameIn= "";
String attackLocationIn= "";
while (read.hasNext())
{
attackIdIn = Integer.parseInt(read.next());
monsterNameIn = read.next();
fullDateIn = read.next();
attackVictimsIn = Integer.parseInt(read.next());
attackLocationIn = read.next();
monsterAttacks.add(new MonsterAttack(fullDateIn, attackIdIn, attackVictimsIn, monsterNameIn, attackLocationIn));
}
read.close();
}

What is happening is that at the end of each line there is a newline character, which is currently not a delimiter. So your code is attempting to read it as the first integer of the next line, which it is not. This is causing the parse exception.
To remedy this, you can try adding newline to the list of delimiters for which to scan:
Scanner read = new Scanner(new File("Attacks.txt"));
read.useDelimiter("[,\r\n]+"); // use just \n on Linux
An alternative to this would be to just read in each entire line from the file and split on comma:
String[] parts = read.nextLine().split(",");
attackIdIn = Integer.parseInt(parts[0]);
monsterNameIn = parts[1];
fullDateIn = parts[2];
attackVictimsIn = Integer.parseInt(parts[3]);
attackLocationIn = parts[4];

You can use the Biegeleisen suggestion. Or else you can do as follows.
In your while loop you are using hasNext as condition. Instead of that you can use while (read.hasNextLine()) and get the nextLine inside the loop and then split it by your delimiter and do the processing. That would be a more appropriate approach.
e.g
while (read.hasNextLine()) {
String[] values = scanner.nextLine().split(".");
// do your rest of the logic
}

Put the while loop content in a try catch, and catch for NumberFormatException. So whenever it falls to catch code, you can understand you tried to convert a string to int.
Could help more if your business is explained.

attackLocationIn = read.next(); This value takes as "Here\n 5" because there is no comma between Here and 5 and it has new line character.
so 2nd iteration attackIdIn = Integer.parseInt(read.next()); here read.next() value is "Danezo" it is String and you are trying parse to Integer. That's why you are getting this exception.
What I suggest is use BufferReader to read line by line and split each line with comma. It will be fast also.
Or another solution Add comma at end of each line and use read.next().trim() in your code. That's it it will work with minimal changes to your current code.

Java BufferedReader miss some values

I have problem with BufferedReader.
My source code works fine, but the problem is when I read a value from named pipe it missed some values.
delim="\t";
reader = new BufferedReader(new FileReader("/tmp/base.pip"));
while ((line = reader.readLine())!=null) {
try{
timestamp = Long.parseLong(line.split(delim)[0]);
}
catch(Exception e){
continue;
}
I need to read whole line to get first column value properly.
example
original line : 12345678 A B
readed line: 2345678 A B (missed first bit)
Is there any suggestion to solve this problem?
p.s it works fine, but only a few lines have problem like the above examples.

I've tested your program and it works fine on my computer.
Check your delim String delim = "\t"
Check your file and it has a tab seperator between them.
Check the line value in your program.
If you don't have a tab space, consider using a regular expression which accepts any number of spaces.
String delim = "\\s+";
delim = '\t'
Split cannot take a character as a delimiter. Please check that. It has to be delim = "\t"

Try to split it with Whitspaces and take the first out ouf the array like:
delim = "\\s";
timestamp = Long.parseLong(line.split(delim)[0]);
I think this should solve your problem.

How to read only integers from file?

I got a problem when I'm trying to read int from text file.
I'm using this kind of code
import java.util.Scanner;
import java.io.*;
File fileName =new File( "D:\\input.txt");
try {
Scanner in = new Scanner(fileName);
c = in.nextInt();
n = in.nextInt();
} catch(Exception e){
System.out.println("File not Found!!!");
}
If my text is edit like this
30
40
So it will work (meaning c=30, n=40).
But if I want to edit the text file that will be like this
c=30
n=40
My code will not work.
How can I change my code to read only the numbers and ignore the "c=" and n="
or any others chars besides the numbers?

You need to read your lines using Scanner.nextLine, split each line on =, and then convert the 2nd part to integer.
Remember to do the check - Scanner.hasNextLine before you read any line. So, you need to use a while loop to read each line.
A Simple implementation, you can extend it according to your need: -
while (scanner.hasNextLine()) {
String line = scanner.nextLine();
String[] tokens = line.split("=");
try {
System.out.println(Integer.parseInt(tokens[1]);
} catch (NumberFormatException e) {
e.printStackTrace();
}
}
Now if you want to use those numbers later on, you can also add them in an ArrayList<Integer>.

Following the format you want to use in the input file then it would be better if you make use of java.util.Properties. You won't need to care about the parsing.
Properties props = new Properties();
props.load(new FileInputStream(new File("D:\\input.txt")));
c = Integer.parseInt(props.getProperty("c"));
n = Integer.parseInt(props.getProperty("n"));
You can read more about the simple line-oriented format.

you could read line by line(Scanner.nextLine) and check every character in the line by asking isDigit()

If your data line will always be in the same format x=12345, use a regex to get the numeric value from the line