Develop Reference

php exec() not refreshing Path environment variable

I upgraded my java jvm, and they changed the way they store the location of the jvm in the PATH environment variable.
It sticks "C:\ProgramData\Oracle\Java\javapath;" at the beginning of the Path variable.
Now, the problem is that when I do exec("java blah blah blah"), php can't find the new path. I get
"'java' is not recognized as an internal or external command, operable program or batch file."
It only works if I do the full path:
exec("c:\My\Path\To\Java\java blah blah blah")
When I do phpInfo(INFO_ENVIRONMENT), it shows the Path variable from before the change. Is it being cached somewhere? I read in other threads that restarting the server, or restarting Apache would help, but it doesn't seem to be working. I tried multiple restarts.
var_dump($_SERVER['PATH']), var_dump(getenv('PATH')) seem to show the NEW path. Why would the value in phpInfo be different? Is there a separate copy of the Path variable somewhere?
I have a development environment that I tested on Windows Vista, and I don't have this problem. When I test it on a windows 2008 environment, I get the problem.
I'm trying to avoid hard coding the path.

before the exec statement you can add the path to the path variable like so
putenv('PATH='.getenv('PATH').'path to java here');

The .exe I created with Launch4j doesn't run

I was able to successfully create a .exe file from an executable jar. From Launch4j I can test the wrapper, and the output on the log is what I expect. However if I try to run the exe from the command line or from Windows Explorer, nothing happens. No error, no output to the console as expected. The program is also supposed to edit a text file which does happen when I run the jar using a batch file, but not when I run the exe. This is all on the same computer so I doubt it is a problem with the JRE. I have searched StackOverflow extensively but found nothing that helps with this situation. I did find this post with a similar problem: Launch4J executable not executing as expected but nobody actually answered the question. Thank you in advance for helping

I found the issue. Under Header, I had to switch the Header type from GUI to Console. After that I was able to run the exe.

You may be accepting something as a command line argument which may be throwing an error like in my case .

For my case, it was the tick on "Signle Instance" tab: Allow only a single instance of the application.
Although I had killed the process, for some unknown reason the exe had been recognized as alive. Thus, a reboot of the PC is recommended.

These are the things I had to do for it to work on Windows 10:
First, make sure the executable JAR you created actually executes. I could never got the JAR to execute by double-clicking. Instead, I created a .bat file where I added the java -jar command-line instruction to execute the jar, including the VM arguments. For example, to execute foo.jar, the .bat file should contain java -jar --module-path %FX_HOME% --add-modules javafx.controls,javafx.fxml foo.jar. Once you get the JAR to execute without errors (pay attention to the command prompt window), then your JAR is ready. Then, do the following from the Launch4J app:
Create FX_HOME environment variable. Make sure it points to the lib folder of the downloaded Java FX distribution is located.*
Set JAVA_HOME environment variable.*
Make sure JAVA_HOME is the first entry on the Path variable. Verify by opening a command prompt and typing where java and hitting the ENTER key.
Under Header, make sure "GUI" is selected.
Under JRE, set Bundled JRE paths to %JAVA_HOME%.
Under VM Option, enter --module-path %FX_HOME% --add-modules javafx.controls,javafx.fxml
*If any of the paths contain spaces, make sure they are in quotes when you create the environment variable. For example: C:\Program Files\Java 17\bin, should be in quotes. This is because the command-line parameters are space-delimited and "Program Files" contains a space, fooling the command-line interpreter to think Program is the end of one parameter and Files is the beginning of another. By putting in quotes, the interpreter now knows the space is part of that single parameter that represents the path.

Running a JAVA program as a scheduled task

I am trying to run a simple JAVA program once per day on a Windows 7 machine.
My code runs fine inside NetBeans. If I do a clean and build it suggests this:
C:\Program Files\Java\jdk1.7.0/bin/java -jar "C:\Users\User1\Documents\NetBeansProjects\Facebook\dist\Facebook.jar"
This does not work from the DOS prompt of course because of the space between program and files so I do this:
C:\Program Files\Java\jdk1.7.0/bin/java -jar "C:\Users\User1\Documents\NetBeansProjects\Facebook\dist\Facebook.jar" -jar "C:\Users\User1\Documents\NetBeansProjects\Facebook\dist\Facebook.jar"
This works from the DOS prompt.
I now create a task in Windows Scheduler to run:
C:\Program Files\Java\jdk1.7.0/bin/java
with arguments:
-jar "C:\Users\User1\Documents\NetBeansProjects\Facebook\dist\Facebook.jar"
When I then run it, all I see is a DOS box flashing up for a second. I expect the code to take about 30 secs to run. The code should persist data to a database and no updates happen.
The code also uses java.util.logging so I should see log entries and I don't.
I strongly suspect that I am not running the JAVA command properly or that there's a bad classpath issue that it present when running via Scheduler that isn't there when running from the DOS prompt.
Help would be appreciated. If you've seen this before and can sort it that would be great. If you can tell me how to get a meaningful error trace from Scheduler than that would also be really helpful.
Thanks!

I Think that you could create a simple batch script that will launch your program in this way :
#echo off
REM Eventually change directory to the program directory
cd C:\Users\User1\Documents\NetBeansProjects\Facebook\dist\
REM run the program
"C:\Program Files\Java\jdk1.7.0\bin\java.exe" -jar "C:\Users\User1\Documents\NetBeansProjects\Facebook\dist\Facebook.jar"
Copy it into the notepad and save as java_script.cmd and then schedule this script instead of the program directly.

I solved it after changing all fonts' references to "SansSerif"
I was using Jasper Reports inside Java to create a PDF file. It was working fine when I double click the batch file or Scheduler with Windows Server 2003 but not working with the Scheduler of 2008.
I tried many different things nothing worked so I though Could it be that Windows Server 2008 is blocking the access?.
Now is working perfect. So, if you are having problems check the references to anything you are using.

The scheduler will run under a different user unless you specify what user to run as. If it isn't running as your user then it won't be able to write to your directories.

The real problem to the original question is a java installation issue on Microsoft systems. Java jre installs into Program Files\java. The executable (java.exe) is only installed in that java\bin directory. Running from the command line, the os looks in the proper location for the java.exe. Running from other MS tools (such as VBA Excel or in this case TaskScheduler), it does not!
You can see that TaskScheduler is looking in the wrong place by viewing the tasks history in the TaskScheduler tool. Double click on some of the history events and one will list the action and return code. The action will show that the TaskScheduler is trying to run
"C:\Windows\system32\java.EXE"
So, copy java.exe from the java\bin directory into the place where the scheduler is looking, and now it will work.
Or update your task and provide the full path to java.exe.
You can also update the environment system path to look for java in the java\bin directory, but that has to apply to all users and sometimes this is faulty as well.

Runtime exec output path

I am trying to run a perl command with Java runtime exec in linux/ubuntu/gnome. The command generates an pdf file, but it saves it in my home folder. Is there any way that the exec method can set an output path for the commands executed? Thanks in advance.

The exec method just runs the command on the operating system, so you'll want to change the command you're running with exec more than anything in "Java" per se.
There are a few possibilities:
Change the working directory of your java program. The .pdf is being saved in your working directory because this is where the program is being run.
Unfortunately it's not simple to change this value after the program has been launched. It is, however, trivial to change before the program starts; just change the working directory before starting the program.
Move the file to it's desired location after it's been created in your home directory.
Change the command so that it includes the target location. Your perl script may have an option that will enable you to save it's output to a certain location (usually -o or --output). Using this your program would change from:
Runtime.exec("perl someprogram");
to something like:
Runtime.exec("perl someprogram -o /path/to/some.file")
You might be able to use "output redirection", if there is no option to do this.
Try something like what's below as your argument:
Runtime.exec("perl someprogram > /path/to/some.file")
Unfortunately, without knowing more details of your situation I can't provide more concrete advice.
While each approach has benefits and drawbacks, it's probably best to just implement the one that you understand best; if you can't get one to work, try another.
A good, free online resource for learning is Introduction to Linux: A Hands On Guide.
Section 2.2 has details on cd which you can use for 1..
Section 3.3, section 3 teaches about the mv command, which will be useful in 2..
Section 5.1 is about I/O redirection. Knowing about "output redirection" and the > operator, are important for 4..
For 3., you'll have to consult the documentation of the perl program you're using.

You could modify the Perl script to accept an absolute path for the output.
You can trying setting the working directory using exec(java.lang.String[], java.lang.String[], java.io.File) where File is the directory the command is executed from.
If all else fails, you'll can always copy the generated file from the Home directory to your final location.

'javac' cannot be found problem

I have a Java application hosted on a remote tomcat instance that executes a bat file which contains the following line
javac filename.java
I receive the following error :-
'javac' is not recognized as an
internal or external command, operable
program or batch file.
I have set the path in the environmental variables. I tried running the same bat file on the machine, it works(which means there is nothing wrong with the path). But running it through the application gives the error. What might be the problem?

Setting the correct path in your environment does not fix the path in the environment of the running tomcat process. If you changed the path in the system settings, a tomcat restart (or system reboot) probably solves your problem.

Once you add %JAVA_HOME%\bin to the PATH var on the remote machine (assuming you have %JAVA_HOME% set there), you will need to run up a new cmd window for the new PATH to be available.

You should set the classpath for the user who is executing tomcat, not only for your login user.

If you have the JRE installed, and not the JDK, you'd be able to run Tomcat but there wouldn't be a javac.exe. Go to JAVA_HOME/bin and see if there's a javac.exe. If not, you have the JRE installed, and you'll have to go get the JDK.
Just curious - why is your Tomcat app calling javac.exe? Are you creating classes on the fly? If yes, why would you not be generating byte code using ASM instead?