Develop Reference

Get absolute path of java app on Heroku [duplicate]

I want to access my current working directory using Java.
My code:
String currentPath = new java.io.File(".").getCanonicalPath();
System.out.println("Current dir:" + currentPath);
String currentDir = System.getProperty("user.dir");
System.out.println("Current dir using System:" + currentDir);
Output:
Current dir: C:\WINDOWS\system32
Current dir using System: C:\WINDOWS\system32
My output is not correct because the C drive is not my current directory.
How to get the current directory?

Code :
public class JavaApplication {
public static void main(String[] args) {
System.out.println("Working Directory = " + System.getProperty("user.dir"));
}
}
This will print the absolute path of the current directory from where your application was initialized.
Explanation:
From the documentation:
java.io package resolve relative pathnames using current user directory. The current directory is represented as system property, that is, user.dir and is the directory from where the JVM was invoked.

See: Path Operations (The Java™ Tutorials > Essential Classes > Basic I/O).
Using java.nio.file.Path and java.nio.file.Paths, you can do the following to show what Java thinks is your current path. This for 7 and on, and uses NIO.
Path currentRelativePath = Paths.get("");
String s = currentRelativePath.toAbsolutePath().toString();
System.out.println("Current absolute path is: " + s);
This outputs:
Current absolute path is: /Users/george/NetBeansProjects/Tutorials
that in my case is where I ran the class from.
Constructing paths in a relative way, by not using a leading separator to indicate you are constructing an absolute path, will use this relative path as the starting point.

The following works on Java 7 and up (see here for documentation).
import java.nio.file.Paths;
Paths.get(".").toAbsolutePath().normalize().toString();

This will give you the path of your current working directory:
Path path = FileSystems.getDefault().getPath(".");
And this will give you the path to a file called "Foo.txt" in the working directory:
Path path = FileSystems.getDefault().getPath("Foo.txt");
Edit :
To obtain an absolute path of current directory:
Path path = FileSystems.getDefault().getPath(".").toAbsolutePath();
* Update *
To get current working directory:
Path path = FileSystems.getDefault().getPath("").toAbsolutePath();

Java 11 and newer
This solution is better than others and more portable:
Path cwd = Path.of("").toAbsolutePath();
Or even
String cwd = Path.of("").toAbsolutePath().toString();

This is the solution for me
File currentDir = new File("");

What makes you think that c:\windows\system32 is not your current directory? The user.dir property is explicitly to be "User's current working directory".
To put it another way, unless you start Java from the command line, c:\windows\system32 probably is your CWD. That is, if you are double-clicking to start your program, the CWD is unlikely to be the directory that you are double clicking from.
Edit: It appears that this is only true for old windows and/or Java versions.

Use CodeSource#getLocation().
This works fine in JAR files as well. You can obtain CodeSource by ProtectionDomain#getCodeSource() and the ProtectionDomain in turn can be obtained by Class#getProtectionDomain().
public class Test {
public static void main(String... args) throws Exception {
URL location = Test.class.getProtectionDomain().getCodeSource().getLocation();
System.out.println(location.getFile());
}
}

this.getClass().getClassLoader().getResource("").getPath()

generally, as a File object:
File getCwd() {
return new File("").getAbsoluteFile();
}
you may want to have full qualified string like "D:/a/b/c" doing:
getCwd().getAbsolutePath()

I'm on Linux and get same result for both of these approaches:
#Test
public void aaa()
{
System.err.println(Paths.get("").toAbsolutePath().toString());
System.err.println(System.getProperty("user.dir"));
}
Paths.get("") docs
System.getProperty("user.dir") docs

I hope you want to access the current directory including the package i.e. If your Java program is in c:\myApp\com\foo\src\service\MyTest.java and you want to print until c:\myApp\com\foo\src\service then you can try the following code:
String myCurrentDir = System.getProperty("user.dir")
+ File.separator
+ System.getProperty("sun.java.command")
.substring(0, System.getProperty("sun.java.command").lastIndexOf("."))
.replace(".", File.separator);
System.out.println(myCurrentDir);
Note: This code is only tested in Windows with Oracle JRE.

On Linux when you run a jar file from terminal, these both will return the same String: "/home/CurrentUser", no matter, where youre jar file is. It depends just on what current directory are you using with your terminal, when you start the jar file.
Paths.get("").toAbsolutePath().toString();
System.getProperty("user.dir");
If your Class with main would be called MainClass, then try:
MainClass.class.getProtectionDomain().getCodeSource().getLocation().getFile();
This will return a String with absolute path of the jar file.

Using Windows user.dir returns the directory as expected, but NOT when you start your application with elevated rights (run as admin), in that case you get C:\WINDOWS\system32

Mention that it is checked only in Windows but i think it works perfect on other Operating Systems [Linux,MacOs,Solaris] :).
I had 2 .jar files in the same directory . I wanted from the one .jar file to start the other .jar file which is in the same directory.
The problem is that when you start it from the cmd the current directory is system32.
Warnings!
The below seems to work pretty well in all the test i have done even
with folder name ;][[;'57f2g34g87-8+9-09!2##!$%^^&() or ()%&$%^##
it works well.
I am using the ProcessBuilder with the below as following:
🍂..
//The class from which i called this was the class `Main`
String path = getBasePathForClass(Main.class);
String applicationPath= new File(path + "application.jar").getAbsolutePath();
System.out.println("Directory Path is : "+applicationPath);
//Your know try catch here
//Mention that sometimes it doesn't work for example with folder `;][[;'57f2g34g87-8+9-09!2##!$%^^&()`
ProcessBuilder builder = new ProcessBuilder("java", "-jar", applicationPath);
builder.redirectErrorStream(true);
Process process = builder.start();
//...code
🍂getBasePathForClass(Class<?> classs):
/**
* Returns the absolute path of the current directory in which the given
* class
* file is.
*
* #param classs
* #return The absolute path of the current directory in which the class
* file is.
* #author GOXR3PLUS[StackOverFlow user] + bachden [StackOverFlow user]
*/
public static final String getBasePathForClass(Class<?> classs) {
// Local variables
File file;
String basePath = "";
boolean failed = false;
// Let's give a first try
try {
file = new File(classs.getProtectionDomain().getCodeSource().getLocation().toURI().getPath());
if (file.isFile() || file.getPath().endsWith(".jar") || file.getPath().endsWith(".zip")) {
basePath = file.getParent();
} else {
basePath = file.getPath();
}
} catch (URISyntaxException ex) {
failed = true;
Logger.getLogger(classs.getName()).log(Level.WARNING,
"Cannot firgue out base path for class with way (1): ", ex);
}
// The above failed?
if (failed) {
try {
file = new File(classs.getClassLoader().getResource("").toURI().getPath());
basePath = file.getAbsolutePath();
// the below is for testing purposes...
// starts with File.separator?
// String l = local.replaceFirst("[" + File.separator +
// "/\\\\]", "")
} catch (URISyntaxException ex) {
Logger.getLogger(classs.getName()).log(Level.WARNING,
"Cannot firgue out base path for class with way (2): ", ex);
}
}
// fix to run inside eclipse
if (basePath.endsWith(File.separator + "lib") || basePath.endsWith(File.separator + "bin")
|| basePath.endsWith("bin" + File.separator) || basePath.endsWith("lib" + File.separator)) {
basePath = basePath.substring(0, basePath.length() - 4);
}
// fix to run inside netbeans
if (basePath.endsWith(File.separator + "build" + File.separator + "classes")) {
basePath = basePath.substring(0, basePath.length() - 14);
}
// end fix
if (!basePath.endsWith(File.separator)) {
basePath = basePath + File.separator;
}
return basePath;
}

assume that you're trying to run your project inside eclipse, or netbean or stand alone from command line. I have write a method to fix it
public static final String getBasePathForClass(Class<?> clazz) {
File file;
try {
String basePath = null;
file = new File(clazz.getProtectionDomain().getCodeSource().getLocation().toURI().getPath());
if (file.isFile() || file.getPath().endsWith(".jar") || file.getPath().endsWith(".zip")) {
basePath = file.getParent();
} else {
basePath = file.getPath();
}
// fix to run inside eclipse
if (basePath.endsWith(File.separator + "lib") || basePath.endsWith(File.separator + "bin")
|| basePath.endsWith("bin" + File.separator) || basePath.endsWith("lib" + File.separator)) {
basePath = basePath.substring(0, basePath.length() - 4);
}
// fix to run inside netbean
if (basePath.endsWith(File.separator + "build" + File.separator + "classes")) {
basePath = basePath.substring(0, basePath.length() - 14);
}
// end fix
if (!basePath.endsWith(File.separator)) {
basePath = basePath + File.separator;
}
return basePath;
} catch (URISyntaxException e) {
throw new RuntimeException("Cannot firgue out base path for class: " + clazz.getName());
}
}
To use, everywhere you want to get base path to read file, you can pass your anchor class to above method, result may be the thing you need :D
Best,

For Java 11 you could also use:
var path = Path.of(".").toRealPath();

This is a very confuse topic, and we need to understand some concepts before providing a real solution.
The File, and NIO File Api approaches with relative paths "" or "." uses internally the system parameter "user.dir" value to determine the return location.
The "user.dir" value is based on the USER working directory, and the behavior of that value depends on the operative system, and the way the jar is executed.
For example, executing a JAR from Linux using a File Explorer (opening it by double click) will set user.dir with the user home directory, regardless of the location of the jar. If the same jar is executed from command line, it will return the jar location, because each cd command to the jar location modified the working directory.
Having said that, the solutions using Java NIO, Files or "user.dir" property will work for all the scenarios in the way the "user.dir" has the correct value.
String userDirectory = System.getProperty("user.dir");
String userDirectory2 = new File("").getAbsolutePath();
String userDirectory3 = Paths.get("").toAbsolutePath().toString();
We could use the following code:
new File(MyApp.class.getProtectionDomain()
.getCodeSource()
.getLocation()
.toURI().getPath())
.getParent();
to get the current location of the executed JAR, and personally I used the following approach to get the expected location and overriding the "user.dir" system property at the very beginning of the application. So, later when the other approaches are used, I will get the expected values always.
More details here -> https://blog.adamgamboa.dev/getting-current-directory-path-in-java/
public class MyApp {
static {
//This static block runs at the very begin of the APP, even before the main method.
try{
File file = new File(MyApp.class.getProtectionDomain().getCodeSource()
.getLocation().toURI().getPath());
String basePath = file.getParent();
//Overrides the existing value of "user.dir"
System.getProperties().put("user.dir", basePath);
}catch(URISyntaxException ex){
//log the error
}
}
public static void main(String args []){
//Your app logic
//All these approaches should return the expected value
//regardless of the way the jar is executed.
String userDirectory = System.getProperty("user.dir");
String userDirectory2 = new File("").getAbsolutePath();
String userDirectory3 = Paths.get("").toAbsolutePath().toString();
}
}
I hope this explanation and details are helpful to others...

Current working directory is defined differently in different Java implementations. For certain version prior to Java 7 there was no consistent way to get the working directory. You could work around this by launching Java file with -D and defining a variable to hold the info
Something like
java -D com.mycompany.workingDir="%0"
That's not quite right, but you get the idea. Then System.getProperty("com.mycompany.workingDir")...

This is my silver bullet when ever the moment of confusion bubbles in.(Call it as first thing in main). Maybe for example JVM is slipped to be different version by IDE. This static function searches current process PID and opens VisualVM on that pid. Confusion stops right there because you want it all and you get it...
public static void callJVisualVM() {
System.out.println("USER:DIR!:" + System.getProperty("user.dir"));
//next search current jdk/jre
String jre_root = null;
String start = "vir";
try {
java.lang.management.RuntimeMXBean runtime =
java.lang.management.ManagementFactory.getRuntimeMXBean();
String jvmName = runtime.getName();
System.out.println("JVM Name = " + jvmName);
long pid = Long.valueOf(jvmName.split("#")[0]);
System.out.println("JVM PID = " + pid);
Runtime thisRun = Runtime.getRuntime();
jre_root = System.getProperty("java.home");
System.out.println("jre_root:" + jre_root);
start = jre_root.concat("\\..\\bin\\jvisualvm.exe " + "--openpid " + pid);
thisRun.exec(start);
} catch (Exception e) {
System.getProperties().list(System.out);
e.printStackTrace();
}
}

This isn't exactly what's asked, but here's an important note: When running Java on a Windows machine, the Oracle installer puts a "java.exe" into C:\Windows\system32, and this is what acts as the launcher for the Java application (UNLESS there's a java.exe earlier in the PATH, and the Java app is run from the command-line). This is why File(".") keeps returning C:\Windows\system32, and why running examples from macOS or *nix implementations keep coming back with different results from Windows.
Unfortunately, there's really no universally correct answer to this one, as far as I have found in twenty years of Java coding unless you want to create your own native launcher executable using JNI Invocation, and get the current working directory from the native launcher code when it's launched. Everything else is going to have at least some nuance that could break under certain situations.

Try something like this I know I am late for the answer but this obvious thing happened in java8 a new version from where this question is asked but..
The code
import java.io.File;
public class Find_this_dir {
public static void main(String[] args) {
//some sort of a bug in java path is correct but file dose not exist
File this_dir = new File("");
//but these both commands work too to get current dir
// File this_dir_2 = new File(this_dir.getAbsolutePath());
File this_dir_2 = new File(new File("").getAbsolutePath());
System.out.println("new File(" + "\"\"" + ")");
System.out.println(this_dir.getAbsolutePath());
System.out.println(this_dir.exists());
System.out.println("");
System.out.println("new File(" + "new File(" + "\"\"" + ").getAbsolutePath()" + ")");
System.out.println(this_dir_2.getAbsolutePath());
System.out.println(this_dir_2.exists());
}
}
This will work and show you the current path but I don't now why java fails to find current dir in new File(""); besides I am using Java8 compiler...
This works just fine I even tested it new File(new File("").getAbsolutePath());
Now you have current directory in a File object so (Example file object is f then),
f.getAbsolutePath() will give you the path in a String varaible type...
Tested in another directory that is not drive C works fine

My favorite method is to get it from the system environment variables attached to the current running process. In this case, your application is being managed by the JVM.
String currentDir = System.getenv("PWD");
/*
/home/$User/Documents/java
*/
To view other environment variables that you might find useful like, home dir, os version ........
//Home directory
String HomeDir = System.getEnv("HOME");
//Outputs for unix
/home/$USER
//Device user
String user = System.getEnv("USERNAME");
//Outputs for unix
$USER
The beautiful thing with this approach is that all paths will be resolved for all types of OS platform

You might use new File("./"). This way isDirectory() returns true (at least on Windows platform). On the other hand new File("") isDirectory() returns false.

None of the answers posted here worked for me. Here is what did work:
java.nio.file.Paths.get(
getClass().getProtectionDomain().getCodeSource().getLocation().toURI()
);
Edit: The final version in my code:
URL myURL = getClass().getProtectionDomain().getCodeSource().getLocation();
java.net.URI myURI = null;
try {
myURI = myURL.toURI();
} catch (URISyntaxException e1)
{}
return java.nio.file.Paths.get(myURI).toFile().toString()

System.getProperty("java.class.path")

Unexpected interaction with String and File

I have following pieces of code:
if (e.getSource() == theView.addButton) {
System.out.println("Add Button clicked");
theView.setBotTextArea("Adding category...");
File directory = new File(theModel.getDirectory() + theView.getCategoryNameInput());
boolean isDirectoryCreated = directory.mkdir();
if(isDirectoryCreated) {
System.out.println("Created new directory in: " + directory);
} else if (directory.exists()) {
System.out.println("Category already exists!");
}
}
This is part of the ActionListener's ActionPerformed() method.
private File directory = new File("C:/Users/Lotix/Desktop/TestFolder/");
public File getDirectory() {
return directory;
}
What i expect this method to do is to create a subfolder in the chosen directory. However, for some reason unknown to me, it creates completly another folder on my desktop instead of TestFolder.
I tried theModel.getDirectory().toString() and manipulating the variable but to no avail. The solution i came up with is to simply add forward slash between
theModel.getDirectory() and theView.getCategoryNameInput() such as this:
File directory = new File(theModel.getDirectory() + "/" + theView.getCategoryNameInput());
However, when i concatenate File variable with another String it works perfectly fine.
What gives?

Any file you create in your own Desktop directory appears on your desktop. That's what the folder is for.
This doesnt have anything to do with 'interaction with String and File', or Java.

Java, cannot delete file on Windows

I have a simple updater for my application. In code i am downloading a new version, deleting old version and renaming new version to old.
It works fine on Linux. But doesn't work on Windows. There are no excepions or something else.
p.s. RemotePlayer.jar it is currently runned application.
UPDATED:
Doesn't work - it means that after file.delete() and file.renameTo(...) file still alive.
I use sun java 7. (because I use JavaFX).
p.s. Sorry for my English.
public void checkUpdate(){
new Thread(new Runnable() {
#Override
public void run() {
System.err.println("Start of checking for update.");
StringBuilder url = new StringBuilder();
url.append(NetworkManager.SERVER_URL).append("/torock/getlastversionsize");
File curJarFile = null;
File newJarFile = null;
try {
curJarFile = new File(new File(".").getCanonicalPath() + "/Player/RemotePlayer.jar");
newJarFile = new File(new File(".").getCanonicalPath() + "/Player/RemotePlayerTemp.jar");
if (newJarFile.exists()){
newJarFile.delete();
}
} catch (IOException e) {
e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates.
System.err.println("Cannot find curr Jar file");
return;
}
if (curJarFile.exists()){
setAccesToFile(curJarFile);
try {
String resp = NetworkManager.makeGetRequest(url.toString());
JSONObject jsresp = new JSONObject(resp);
if (jsresp.getString("st").equals("ok")){
if (jsresp.getInt("size") != curJarFile.length()){
System.out.println("New version available, downloading started.");
StringBuilder downloadURL = new StringBuilder();
downloadURL.append(NetworkManager.SERVER_URL).append("/torock/getlatestversion");
if (NetworkManager.downLoadFile(downloadURL.toString(), newJarFile)){
if (jsresp.getString("md5").equals(Tools.md5File(newJarFile))){
setAccesToFile(newJarFile);
System.err.println("Deleting old version. File = " + curJarFile.getCanonicalPath());
boolean b = false;
if (curJarFile.canWrite() && curJarFile.canRead()){
curJarFile.delete();
}else System.err.println("Cannot delete cur file, doesn't have permission");
System.err.println("Installing new version. new File = " + newJarFile.getCanonicalPath());
if (curJarFile.canWrite() && curJarFile.canRead()){
newJarFile.renameTo(curJarFile);
b = true;
}else System.err.println("Cannot rename new file, doesn't have permission");
System.err.println("last version has been installed. new File = " + newJarFile.getCanonicalPath());
if (b){
Platform.runLater(new Runnable() {
#Override
public void run() {
JOptionPane.showMessageDialog(null, String.format("Внимание, %s", "Установлена новая версия, перезапустите приложение" + "", "Внимание", JOptionPane.ERROR_MESSAGE));
}
});
}
}else System.err.println("Downloading file failed, md5 doesn't match.");
}
} else System.err.println("You use latest version of application");
}
}catch (Exception e){
e.printStackTrace();
System.err.println("Cannot check new version.");
}
}else {
System.err.println("Current jar file not found");
}
}
}).start();
}
private void setAccesToFile(File f){
f.setReadable(true, false);
f.setExecutable(true, false);
f.setWritable(true, false);
}

I found the solution to this problem. The problem of deletion occurred in my case because-:
File f1=new File("temp.txt");
RandomAccessFile raf=new RandomAccessFile(f1,"rw");
f1.delete();//The file will not get deleted because raf is open on the file to be deleted
But if I close RandomAccessFile before calling delete then I am able to delete the file.
File f1=new File("temp.txt");
RandomAccessFile raf=new RandomAccessFile(f1,"rw");
raf.close();
f1.delete();//Now the file will get deleted
So we must check before calling delete weather any object such as FileInputStream, RandomAccessFile is open on that file or not. If yes then we must close that object before calling delete on that file.

windows locks files that are currently in use. you cannot delete them. on windows, you cannot delete a jar file which your application is currently using.

Since you are using Java 7, try java.nio.file.Files.delete(file.toPath()), it'll throw exception if deletion fails.

There are several reasons:
Whether you have permissions to edit the file in windows.
The file is in use or not.
The path is right or not.

I don't know wich version of Java you are using.
I know when Java was sun property they publish that the Object File can't delete files correctly on windows plateform (sorry I don't find the reference no more).
The tricks you can do is to test the plateform directly. When you are on linux just use the classic File object.
On windows launch a command system to ask windows to delete the file you want.
Runtime.getRuntime().exec(String command);

I just want to make one comment. I learned that you can delete files in Java from eclipse if you run eclipse program as Administrator. I.e. when you right click on the IDE Icon (Eclipse or any other IDE) and select Run as Administrator, Windows lets you delete the file.
I hope this helps. It helped me.
Cordially,
Fernando

Java formatter - setting file directory

i am trying to create a text file in a folder (called AMCData). The file is called "File" (for the sake of this example).
I have tried using this code:
public static void OpenFile(String filename)
{
try
{
f = new Formatter("AMCData/" + filename + ".txt");
}
catch(Exception e)
{
System.out.println("error present");
}
}
But before i get the chance to even place any text in it, the catch keeps being triggered..
Could anyone inform me why this is occuring?
more information:
The folder does not exist, i was hoping it would automatically create it
If it doesn't automatically create folders, could you please link me to how to do so?

You're right, a Formatter(String) constructor needs the file to be present or createable. The most likely reason why a file cannot be created is that it references a folder that itself doesn't exist, so you should use the File.mkdirs() method, like this:
new File("AMCData").mkdirs();

Executing JAR file within another java application

I'm trying to run a External Jar file, without actually inserting it into my jar itself. Because the jar file needs to be located in the same folder as the main jar file.
So, Within the main jar file I want to execute the other executable jar file, And I need to be able to know when the jar file is ended AND when you close the main jar file, the jar file that is started within the jar file needs to be closed to,
I currently do that by using this code:
public void LaunchLatestBuild()
{
try {
String path = new File(".").getCanonicalPath() +
"\\externaljar.jar";
List commands = new ArrayList();
commands.add(getJreExecutable().toString());
commands.add("-Xmx" + this.btd_serverram + "M");
commands.add("-Xms" + this.btd_serverram + "M");
commands.add("-jar");
commands.add(path);
int returnint = launch(commands); //It just waits and stops the tread here. And my Runtime.getRuntime().addShutdownHook doesn't get triggerd.
if (returnint != 201) //201 is a custom exit code I 'use' to know when the app needs a restart or not.
{
System.out.println("No restart needed! Closing...");
System.exit(1);
}
else
{
CloseCraftBukkit();
Launcher.main(new String[] { "" });
}
}
catch (Exception e)
{
System.out.println(e.toString());
e.printStackTrace();
}
}
public int launch(List<String> cmdarray) throws IOException, InterruptedException
{
byte[] buffer = new byte[1024];
ProcessBuilder processBuilder = new ProcessBuilder(cmdarray);
processBuilder.redirectErrorStream(true);
this.CBProcess = processBuilder.start();
InputStream in = this.CBProcess.getInputStream();
while (true) {
int r = in.read(buffer);
if (r <= 0) {
break;
}
System.out.write(buffer, 0, r);
}
return this.CBProcess.exitValue();
}
Limitations of this code:
Doesn't close my externaljar.jar java
process on exit of the main
application.
Cannot redirect input if main console, to external jar.
That are the most Important things I need.
I hope someone can tell me how I should do this.
Current source code is available at:
http://code.google.com/p/bukkit-to-date/

Why can't you just set your classpath so that it includes the second jar, and then you can simply use it as a library ? You can even invoke the MainClass.main() method manually, if you really want that to be executed, but from within the same VM and without spawning a separate process.
EDIT: If you don't know the name of the jar file when your application is launched, but you'll only figure that out at runtime, in order to invoke it, create a URLClassLoader provided with the path to your jar file and then:
URLClassLoader urlClassLoader = new URLClassLoader(
new File("/path/to/your/jar/file.jar").toURI().toURL() );
ClassLoader cl = Thread.currentThread().getContextClassLoader();
// switch to your custom CL
Thread.currentThread().setContextClassLoader(urlClassLoader);
// do your stuff with the other jar
// ....................
// now switch back to the original CL
Thread.currentThread().setContextClassLoader(cl);
Or simply grab a reference to a class in that other jar and make use of reflection:
Class<?> c = urlClassLoader.loadClass("org.ogher.packag.ClassFromExternalJar");