Develop Reference

Test works on local Windows machine but fails on Linux server

I have this test:
#Test
void testHeader() {
String inputFile = ".\\src\\main\\resources\\binaryFile";
MDHeader addHeader = new MDHeader();
try (
InputStream inputStream = new FileInputStream(inputFile);
) {
long fileSize = new File(inputFile).length();
byte[] allBytes = new byte[(int) fileSize];
inputStream.read(allBytes);
ProducerRecord<String, byte[]> record = new ProducerRecord<String, byte[]>("foo", allBytes);
ProducerRecord<String, byte[]> hdr = addHeader.addMDHeader(record);
for (Header header : hdr.headers()) {
assertEquals("mdpHeader", header.key());
}
}
catch(Exception e) {
assert (false);
}
}
The test succeeds when run locally through Eclipse on my Windows desktop but it fails at com.me.be.HeaderTests.testMDHeader(HeaderTests.java:81) when trying to build the jar on a Linux server. That's the line assert (false). I haven't got any more information on the issue yet but was wondering if it could be the backslashes in inputFile in a Linux environment?

Java on Windows and Linux will both accept / as path separator, whereas Linux does not like \\ as a path separator - so treats the whole string as ONE path component, not 4 parts as you'd expect:
String inputFile = "./src/main/resources/binaryFile";
However for file handling it is better to use java.nio.Path or java.io.File in place of String.
WINDOWS
jshell> Path.of("./src/main/resources/binaryFile")
$2 ==> .\src\main\resources\binaryFile
Linux
jshell> Path.of("./src/main/resources/binaryFile")
$1 ==> ./src/main/resources/binaryFile
You can also use Path.of without any file separator for any OS:
Path p = Path.of("src","main","resources","binaryFile");

The File.separator string is handy to concat into the path string in order to produce an OS independent file path.
String inputFile = "." + File.separator + "src" + File.separator + "main" + File.separator + "resources" + File.separator + "binaryFile";
Should give you a cross platform compliant file path.

Java get resource is not working

I try to read a resource file from my application but it doesn't work.
Code:
String filename = getClass().getClassLoader().getResource("test.xsd").getFile();
System.out.println(filename);
File file = new File(filename);
System.out.println(file.exists());
Output when I execute the jar-file:
file:/C:/Users/username/Repo/run/Application.jar!/test.xsd
false
It works when I run the application from IntelliJ but not when I execute the jar-file. If I open my jar-file with 7-zip test.xsd is located in the root-folder. Why isn't the code working when I execute the jar-file?

Also, File refers to actual OS file-system files; in the OS's file-system, there is only a jar file, and that jar file is not a folder. You should either extract the contents of the URL to a temporary file, or operate with its bytes in-memory or as a stream.
Note that myURL.getFile() is returning a String representation, and not an actual File. In a similar way, this will not work:
File f = new URL("http://www.example.com/docs/resource1.html").getFile();
f.exists(); // always false - will not be found in the local filesystem
A nice wrapper could be the following:
public static File openResourceAsTempFile(ClassLoader loader, String resourceName)
throws IOException {
Path tmpPath = Files.createTempFile(null, null);
try (InputStream is = loader.getResourceAsStream(resourceName)) {
Files.copy(is, tmpPath, StandardCopyOption.REPLACE_EXISTING);
return tmpPath.toFile();
} catch (Exception e) {
if (Files.exists(tmpPath)) Files.delete(tmpPath);
throw new IOException("Could not create temp file '" + tmpPath
+ "' for resource '" + resourceName + "': " + e, e);
}
}

How to pass arguments to pre compiled java code

I need to process a high volume of resumes. And want to use this parser:
https://github.com/antonydeepak/ResumeParser
But you run it in powershell with the file to read and the output file.
But I do not know how to automate this, so it read a whole folder containing the resumes.
I know some Java, but cant open the code. Is scripinting in powershell the way to go?
Thanks!

> java -cp '.\bin\*;..\GATEFiles\lib\*;..\GATEFILES\bin\gate.jar;.\lib\*'
code4goal.antony.resumeparser.ResumeParserProgram <input_file> [output_file]
Either make a batch file from an edited directory listing, or write a program.
As this is stackoverflow:
So starting with the same classpath (-cp ...) you can run your own program
public void static main(String[] args) throws IOException {
File[] files = new File("C:/resumes").listFiles();
File outputDir = new File("C:/results");
outputDir.mkDirs();
if (files != null) {
for (File file : files) {
String path = file.getPath();
if (path.endsWith(".pdf")) {
String output = new File(outputDir,
file.getName().replaceFirst("\\.\\w+$", "") + ".json").getPath();
String[] params = {path, output);
ResumeParserProgram.main(params);
// For creating a batch file >x.bat
System.out.println("java -cp"
+ " '.\\bin\\*;..\\GATEFiles\lib\\*;"
+ "..\\GATEFILES\\bin\\gate.jar;.\\lib\\*'"
+ " code4goal.antony.resumeparser.ResumeParserProgram"
+ " \"" + path + "\" \"" + output + "\"");
}
}
}
}
Check that this works, that ResumeParserProgram.main is reenterable.

log4j doesn't write file on windows

I'm having problems with my program on Windows, I included logging, so that I can find the specific cause of the issue. My program's JavaFX and to start it on windows I build it as .jar file.
I'm setting up a log4j FileAppender through program code, in the config-file (.../MyProject/data/configuration.txt) is the path where to have the log folder. On Mac OS X (debugged with Eclipse) everything is working fine.
If i'm starting the jar on Windows (.../MyProject/build/dist/MyProgram.jar) and see the configured log folder, i don't see any log file created. (I figured out that the config file than has to be under .../MyProject/build/dist/data/configuration.txt) If i write new subfolders to the log directory's path, the program creates them, but there's no file!
My code:
String computername = "";
try {
computername = InetAddress.getLocalHost().getHostName();
} catch (UnknownHostException e) {
e.printStackTrace();
}
int tid = (int)Thread.currentThread().getId();
PatternLayout playout = new PatternLayout("%d{yyyy-MM-dd'T'HH:mm:ss.SSSZ}; %p; %F:%L; " + computername + "; " + tid + "; [%t]; %m;%n");
SimpleDateFormat dt = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");
Date datenow = new Date();
datenow.setTime(datenow.getTime());
FcManagerMain.formatteddate = dt.format(datenow);
try
{
File config = new File ("data/configuration.txt");
BufferedReader bufferedReader = new BufferedReader(new FileReader("data/configuration.txt"));
int count = 1;
String line = null;
while((line = bufferedReader.readLine()) != null)
{
if(count == 3)
{
FcManagerMain.logfolder = line;
}
count++;
}
if(isWindows())
{
File p = new File(FcManagerMain.logfolder + FcManagerMain.version);
p.mkdirs();
File pp = new File(FcManagerMain.logfolder + FcManagerMain.version + "\\" + FcManagerMain.formatteddate + ".log");
pp.createNewFile();
FileAppender fileAppender = new FileAppender(playout, pp.getAbsolutePath(), false);
loggerstatic.addAppender(fileAppender);
loggerstatic.setLevel(Level.ALL);
}
else
{
File p = new File(FcManagerMain.logfolder + FcManagerMain.version);
p.mkdirs();
File pp = new File(FcManagerMain.logfolder + FcManagerMain.version + "/" + FcManagerMain.formatteddate + ".log");
pp.createNewFile();
FileAppender fileAppender = new FileAppender(playout, pp.getAbsolutePath(), false);
loggerstatic.addAppender(fileAppender);
loggerstatic.setLevel(Level.ALL);
}
}
catch(Exception ee)
{
System.out.println(getStackTrace(ee));
}
loggerstatic is a static Logger instance (FcManagerController.loggerstatic) and every other class takes its logger from loggerstatic. I guess that's not correct, please tell me how to do!
EDIT: I have already tried different log locations to see if I don't have permission to write to that specific folders.
Thanks,
rapgru

I'd rather recommend you use the built-in configuration, i. e. adapt the log4j.properties.
Read the documentation, especially the usage of ${log} here:
# Set the name of the file
log4j.appender.FILE.File=${log}/log.out
You declare your own system variable by default and change it via jvm parameter when you start your app:
# log directory (default, 'log' directory relative to the execution path)
# you can override the default directory by setting the variable as VM option when you start the application
# example: -DMYAPP_LOG_DIR=/tmp/logs
MYAPP_LOG_DIR=./log
...
log4j.appender.debugfile.file=${MYAPP_LOG_DIR}/application.log
Then when you start your application and don't want the log file to be in the execution folder, just specify a different path via the -D option.

Create a folder and a file with Java in Ubuntu

Here is what I wanna do:
Check if a folder exists
If it does not exists, create the folder
If it doest exists do nothing
At last create a file in that folder
Everything is working fine in Windows 7, but when I run the application in Ubuntu it doesn't create the folder, it is just creating the file with the folder name, example: (my file name is xxx.xml and the folder is d:\temp, so in Ubuntu the file is generated at d: with the name temp\xxx.xml). Here is my code:
File folder = new File("D:\\temp");
if (folder.exists() && folder.isDirectory()) {
} else {
folder.mkdir();
}
String filePath = folder + File.separator;
File file = new File(filePath + "xxx.xml");
StreamResult result = new StreamResult(file);
transformer.transform(source, result);
// more code here

Linux does not use drive letters (like D:) and uses forward slashes as file separator.
You can do something like this:
File folder = new File("/path/name/of/the/folder");
folder.mkdirs(); // this will also create parent directories if necessary
File file = new File(folder, "filename");
StreamResult result = new StreamResult(file);

You directory (D:\temp) is nos appropriate on Linux.
Please, consider using linux File System, and the File.SEPARATOR constant :
static String OS = System.getProperty("OS.name").toLowerCase();
String root = "/tmp";
if (OS.indexOf("win") >= 0) {
root="D:\\temp";
} else {
root="/";
}
File folder = new File(ROOT + "dir1" + File.SEPARATOR + "dir2");
if (folder.exists() && folder.isDirectory()) {
} else {
folder.mkdir();
}
Didn't tried it, but whould work.

D:\temp does not exists in linux systems (what I mean is it interprets it as if it were any other foldername)
In Linux systems the file seperator is / instead of \ as in case of Windows
so the solution is to :
File folder = new File("/tmp");
instead of
File folder = new File("D:\\temp");

Before Java 7 the File API has some possibilities to create a temporary file, utilising the operating system configuration (like temp files on a RAM disk). Since Java 7 use the utility functions class Files.

Consider both solutions using the getProperty static method of System class.
String os = System.getProperty("os.name");
if(os.indexOf("nix") >= 0 || os.indexOf("nux") >= 0 || os.indexOf("aix") > 0 ) // Unix
File folder = new File("/home/tmp");
else if(os.indexOf("win") >= 0) // Windows
File folder = new File("D:\\temp");
else
throw Exception("your message");

On Unix-like systems no logical discs. You can try create on /tmp or /home
Below code for create temp dirrectory in your home directory:
String myPathCandidate = System.getProperty("os.name").equals("Linux")? System.getProperty("user.home"):"D:\\";
System.out.println(myPathCandidate);
//Check write permissions
File folder = new File(myPathCandidate);
if (folder.exists() && folder.isDirectory() && folder.canWrite()) {
System.out.println("Create directory here");
} else {System.out.println("Wrong path");}
or, for /tmp - system temp dicecrory. Majority of users can write here:
String myPathCandidate = System.getProperty("os.name").equals("Linux")? System.getProperty("java.io.tmpdir"):"D:\\";

Since Java 7, you can use the Files utility class, with the new Path class. Note that exception handling has been omitted in the examples below.
// uses os separator for path/to/folder.
Path file = Paths.get("path","to","file");
// this creates directories in case they don't exist
Files.createDirectories(file.getParent());
if (!Files.exists(file)) {
Files.createFile(file);
}
StreamResult result = new StreamResult(file.toFile());
transformer.transform(source, result);
this covers the generic case, create a folder if it doesn't exist and a file on that folder.
In case you actually want to create a temporary file, as written in your example, then you just need to do the following:
// this create a temporary file on the system's default temp folder.
Path tempFile = Files.createTempFile("xxx", "xml");
StreamResult result = new StreamResult(Files.newOutputStream(file, CREATE, APPEND, DELETE_ON_CLOSE));
transformer.transform(source, result);
Note that with this method, the file name will not correspond exactly to the prefix you used (xxx, in this case).
Still, given that it's a temp file, that shouldn't matter at all. The DELETE_ON_CLOSE guarantees that the file will get deleted when closed.