Develop Reference

how to execute jar file using java [duplicate]

How could I run a local jar file from a java program?
The jar file is not in the class-path of the Java caller program.

I suggest you use a ProcessBuilder and start a new JVM.
Here is something to get you started:
ProcessBuilder pb = new ProcessBuilder("/path/to/java", "-jar", "your.jar");
pb.directory(new File("preferred/working/directory"));
Process p = pb.start();

Process proc = Runtime.getRuntime().exec("java -jar Validate.jar");
proc.waitFor();
// Then retreive the process output
InputStream in = proc.getInputStream();
InputStream err = proc.getErrorStream();
byte b[]=new byte[in.available()];
in.read(b,0,b.length);
System.out.println(new String(b));
byte c[]=new byte[err.available()];
err.read(c,0,c.length);
System.out.println(new String(c));

First, the description of your problem is a bit unclear. I don't understand if you want to load the classes from the jar file to use in your application or the jar contains a main file you want to run. I will assume it is the second.
If so, you have a lot of options here.
The simplest one would be the following:
String filePath; //where your jar is located.
Runtime.exec(" java -jar " + filepath);
Voila...
If you don't need to run the jar file but rather load the classes out of it, let me know.

Could something like the following be useful?
http://download.oracle.com/javase/tutorial/deployment/jar/jarclassloader.html

Another way to do on windows is:
Runtime.getRuntime().exec("cmd /c start jarFile");
this way you can set priority of your process as well (normal/low/etc)

You can run a jar file from where ever you want by using only this one line code.
Desktop.getDesktop().open(new File("D:/FormsDesktop.jar"));
where
new File("your path to jar")
Hope it helps.
Thanks.

Add jar library to your project
Import main class (see manifest in jar file)
Invoke static method main with arguments
String args[] = {"-emaple","value"};
PortMapperStarter.main(args);

To run an executable jar from inside your java application, you can copy the JarClassLoader from https://docs.oracle.com/javase/tutorial/deployment/jar/examples/JarClassLoader.java
Use it like this. In this snippet, jarUrl is the URL to download the jar from, for example file:/tmp/my-jar.jar and args is the array of strings you want to pass as command line arguments to the jar.
JarClassLoader loader = new JarClassLoader(jarUrl);
String main = loader.getMainClassName();
loader.invokeClass(main, args);
Keep in mind that you're now inserting someone else's binary into your code. If it gets stuck in an infinite loop, your Thread hangs, if it calls System.exit(), your JVM exits.

This is my appriach, which I consider is more complete:
public static Process exec(String path, String filename) throws IOException {
String javaHome = System.getProperty("java.home");
String javaBin = javaHome +
File.separator + "bin" +
File.separator + "java";
ProcessBuilder pb = new ProcessBuilder(javaBin, "-jar", path+filename);
return pb.start();
}

1) Set the class path from environment variables
2) Go to the folder where your jar file exists
3) Run the following commands through command prompt
java -jar jarfilename

Runtime.exec(String) limiting String

I'm trying to use the Java function Runetime.exec(String) to run a program in the startup folder of a windows 7 computer like so:
Runtime.getRuntime().exec(runner.getPath() + "\\run.bat");
And when I run this I get an error saying the command cannot be run:
Exception in thread "main" java.io.IOException: Cannot run program ""C:\Users\ly
ndsey\AppData\Roaming\Microsoft\Windows\Start": CreateProcess error=2, The syste
m cannot find the file specified
As you can see, the file name is cut off at the "\Windows\Start" when it should continue to "\Windows\Startup\run.bat".. Is there an alternative I can use?

Considering runner as a File instance, this should work.
Desktop.getDesktop().open(new File(runner, "run.bat"));
It uses Desktop class instead of Runtime, so you don't have to convert your File (runner) to its String representation (which is error prone). Runner is now used 'as is' as the parent directory of the "run.bat" you want to execute.
Other advantage of Desktop class : you can now open any file you want.

As an alternative you can use ProcessBuilder. I feel ProcessBuilder is more safe than Runtime.getRuntime().exec http://docs.oracle.com/javase/7/docs/api/java/lang/ProcessBuilder.html
String[] command = {"CMD", "/C", "dir"};
ProcessBuilder pb = new ProcessBuilder( command );
//set up your work directory if needed
pb.directory(new File("c:\\path"));
Process process = pb.start();

as i can see from the error you give, and i hope it's a copy past, you string runner.getPath() for some reason start and end with "\"" which make the whole path invalid. check that and remove it if needed
if you have the file already and you just need it's path you can use
runner.getAbsolutePath()
also, if runner is a file, getPath will give you the file path including the path, so your code will surely won't work. instead use:
String path = runner.getPath();
path = path.substring(0, path.lastIndexOf("\\")) + "\\run.bat";
Runtime.getRuntime().exec(path);

You should avoid the exec(String) method, which attempts to parse the entire string into command + arguments. The safe option is exec(String[]), which presupposes the first array element is the command and the rest are arguments.
So, writing
Runtime.getRuntime.exec(new String[] { yourCommandString })
is a surefire way of getting the right message across.

java.io.IOException:Cannot run program "sh" (in directory"c:\cygwin\bin\test"):CreateProcess error=2.The system cannot find file specified

I am running shell scripts with the help of java and cygwin. When i am running my code in windows xp it works fine. Now i am trying to run same code on windows 7 i am getting above error.
(java.io.IOException)java.io.IOException:
Cannot run program "sh" (in directory"c:\cygwin\bin\test"):
CreateProcess error=2.The system cannot find file specified
Why this error occurred.I have set my path for cygwin (PATH=.;c:\cygwin\bin) How to avoid this.
ProcessBuilder pb = new ProcessBuilder ();
pb.directory(new File("C:\\cygwin\\bin\\Test\\"));
File shellfile = new File("app.sh");//File name with extension
System.out.println(shellfile.getCanonicalPath());
But it is giving the output as E:\NIRAJ\example\app.sh which is in my java program. even i am setting up pb.directory to the path.
if i check System.out.print(pb.directory()); it gives me output C:\cygwin\bin\Test

In PATH variable, you need to put cygwin's bin directory before any other Windows' paths.
Do this:
PATH=c:\cygwin\bin:RestWindowsPaths
Not that:
PATH=RestWindowsPathVariables:c:\cygwin\bin

First try to get the path of specified file first to ensure it:
I am not much sure but this may lead you one step ahead :
File file = new File("app.sh");//File name with extension
System.out.println(file.getCanonicalPath());
This should print : c:\cygwin\bin\test
Also use separator like this instead : c:\\cygwin\\bin\\test
Hope this helps.
UPDATE
String myCommand = "c:\\cygwin\\bin\\test\\cygbin";
String myArg = PATH_TO_shellscript+"app.sh";
ProcessBuilder p = new ProcessBuilder(myCommand, myArg).start();

Windows xcopy using java Runtime.exec not working for filenames with chinese characters

I currently have a java program that uses xcopy with Runtime.exec to copy files. But the problem now is that when the file name has chinese characters this does not work.
It gives a file not found error.
However if i copy the file path from explorer and do xcopy from the command line copy works.
I am executing it from a Windows 7 machine. Any solutions will be much appreciated.
Thanks
This is related to the bug http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4947220. Instead of passing the parameters as arguments, passed them via environment variables which worked perfectly.

Why are you using xcopy? Use java.
Try to do it with java.nio.file.Files
Path a = ...
Path b = ...
Files.copy(a,b);
See here for doc:
http://docs.oracle.com/javase/7/docs/api/java/nio/file/Files.html#copy(java.nio.file.Path,%20java.nio.file.Path,%20java.nio.file.CopyOption...)

The exec in Java converts the strings to the system code page.
Shameful, for the XXI century, but that's how it is.
But Java is not the only bottleneck here. The console is also problematic, and xcopy might have it's own share.
There is a lot of voodoo that you can try, for instance starting cmd.exe as Unicode (/U), and/or setting the code page to utf-8 (chcp 65001), or create a batch file with the command and call that batch (so no high-ascii in the exec function).
But I would not relay on that.
Since everything is Windows only anyway, I would probably try using jni to implement a "proper" exec, or see if FileCopy is faster than the Java copy.

If you need to copy large files, or files and all the system permissions associated with a file, using java internal File.copy() will be too expensive, so you can offload all the load to your system.
Try the following trick - first, user string array as an argument to exec(); second, execute your 'xcopy' in a pipe after 'cmd' command with /C argument. Look at the sample code near line where I make isWindows() call.
The trick is that your xcopy command will be executed inside CMD shell, and /C will terminate it after successful execution. More aboutCMD.exe.
public int sysCopyFile(Resource fromResource, Resource toResource) throws ServiceException {
int returnCode = -1;
try {
String[] copyCommand = null;
if ( IOUtils.isWindows() ) {
copyCommand = new String[] {"cmd", "/C", "copy", "/Y", fromResource.getFile().getAbsolutePath(), toResource.getFile().getAbsolutePath()};
} else if ( IOUtils.isUnix() || IOUtils.isMac() ) {
copyCommand = new String[] {"/bin/cp", "-pr", fromResource.getFile().getAbsolutePath(),toResource.getFile().getAbsolutePath()};
}
final Process p = Runtime.getRuntime().exec(copyCommand);
new StreamLogger(p.getErrorStream(), log, StreamLogger.WARN);
new StreamLogger(p.getInputStream(), log, StreamLogger.DEBUG);
returnCode = p.waitFor();
if (returnCode != 0) throw new ServiceException("Unable to to copy. Command: {" + copyCommand[0] + "} has returned non-zero returnCode: " + returnCode);
} catch (IOException e) {
throw new ServiceException(e);
} catch (InterruptedException e) {
throw new ServiceException(e);
}
return returnCode;
}

How to use "cd" command using Java runtime?

I've created a standalone java application in which I'm trying to change the directory using the "cd" command in Ubuntu 10.04 terminal. I've used the following code.
String[] command = new String[]{"cd",path};
Process child = Runtime.getRuntime().exec(command, null);
But the above code gives the following error
Exception in thread "main" java.io.IOException: Cannot run program "cd": java.io.IOException: error=2, No such file or directory
Can anyone please tell me how to implement it?

There is no executable called cd, because it can't be implemented in a separate process.
The problem is that each process has its own current working directory and implementing cd as a separate process would only ever change that processes current working directory.
In a Java program you can't change your current working directory and you shouldn't need to. Simply use absolute file paths.
The one case where the current working directory matters is executing an external process (using ProcessBuilder or Runtime.exec()). In those cases you can specify the working directory to use for the newly started process explicitly (ProcessBuilder.directory() and the three-argument Runtime.exec() respectively).
Note: the current working directory can be read from the system property user.dir. You might feel tempted to set that system property. Note that doing so will lead to very bad inconsistencies, because it's not meant to be writable.

See the link below (this explains how to do it):
http://alvinalexander.com/java/edu/pj/pj010016
i.e. :
String[] cmd = { "/bin/sh", "-c", "cd /var; ls -l" };
Process p = Runtime.getRuntime().exec(cmd);

Have you explored this exec command for a java Runtime, Create a file object with the path you want to "cd" to and then input it as a third parameter for the exec method.
public Process exec(String command,
String[] envp,
File dir)
throws IOException
Executes the specified string command in a separate process with the specified environment and working directory.
This is a convenience method. An invocation of the form exec(command, envp, dir) behaves in exactly the same way as the invocation exec(cmdarray, envp, dir), where cmdarray is an array of all the tokens in command.
More precisely, the command string is broken into tokens using a StringTokenizer created by the call new StringTokenizer(command) with no further modification of the character categories. The tokens produced by the tokenizer are then placed in the new string array cmdarray, in the same order.
Parameters:
command - a specified system command.
envp - array of strings, each element of which has environment variable settings in the format name=value, or null if the subprocess should inherit the environment of the current process.
dir - the working directory of the subprocess, or null if the subprocess should inherit the working directory of the current process.
Returns:
A new Process object for managing the subprocess
Throws:
SecurityException - If a security manager exists and its checkExec method doesn't allow creation of the subprocess
IOException - If an I/O error occurs
NullPointerException - If command is null, or one of the elements of envp is null
IllegalArgumentException - If command is empty

This command works just fine
Runtime.getRuntime().exec(sh -c 'cd /path/to/dir && ProgToExecute)

Using one of the process builder's method we could pass the directory where we expect the cmd to be executed. Please see the below example. Also , you can mention the timeout for the process, using wait for method.
ProcessBuilder builder = new ProcessBuilder("cmd.exe", "/c", cmd).directory(new File(path));
Process p = builder.start();
p.waitFor(timeoutSec, TimeUnit.SECONDS);
In the above code, you can pass the file object of the path[where we expect the cmd to be executed] to the directory method of ProcessBuilder

My preferred solution for this is to pass in the directory that the Runtime process will run in. I would create a little method like follows: -
public static String cmd(File dir, String command) {
System.out.println("> " + command); // better to use e.g. Slf4j
System.out.println();
try {
Process p = Runtime.getRuntime().exec(command, null, dir);
String result = IOUtils.toString(p.getInputStream(), Charset.defaultCharset());
String error = IOUtils.toString(p.getErrorStream(), Charset.defaultCharset());
if (error != null && !error.isEmpty()) { // throw exception if error stream
throw new RuntimeException(error);
}
System.out.println(result); // better to use e.g. Slf4j
return result; // return result for optional additional processing
} catch (IOException e) {
throw new RuntimeException(e);
}
}
Note that this uses the Apache Commons IO library i.e. add to pom.xml
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.10.0</version>
</dependency>
To use the cmd method e.g.
public static void main(String[] args) throws Exception {
File dir = new File("/Users/bob/code/test-repo");
cmd(dir, "git status");
cmd(dir, "git pull");
}
This will output something like this: -
> git status
On branch main
Your branch is up to date with 'origin/master'.
nothing to commit, working tree clean
> git pull
Already up to date.

Try Use:
Runtime.getRuntime.exec("cmd /c cd path");
This worked
Runtime r = Runtime.getRuntime();
r.exec("cmd /c pdftk C:\\tmp\\trashhtml_to_pdf\\b.pdf C:\\tmp\\trashhtml_to_pdf\\a.pdf cat output C:\\tmp\\trashhtml_to_pdf\\d.pdf");
The below did not work
While using array command did NOT WORK
String[] cmd = {"cmd /c pdftk C:\\tmp\\trashhtml_to_pdf\\b.pdf C:\\tmp\\trashhtml_to_pdf\\a.pdf cat output C:\\tmp\\trashhtml_to_pdf\\d.pdf"}; r.exec(cmd);
FYI am using utility to check OS if its windows above will work for other than windows remove cmd and /c

I had solved this by having the Java application execute a sh script which was in the same directory and then in the sh script had done the "cd".
It was required that I do a "cd" to a specific directory so the target application could work properly.