In mac OSX and in Linux CentOS, I insert a new system environment variable (i.e. "MYAPP") using .bashrc & .bash_profile. I even restarted my laptop (mac) and my server (linux).
When I use the command line "env", that environment variable showed with the correct value. But somehow every time I try to get it in a Java app (desktop app or web app or EJB or servlet any other java app) in either mac or linux, that environment variable ("MYAPP") is not retrieved.
I tried to iterate through the entire environment variables that Java can retrieve and it turns out that it retrieves every environment variables other than "MYAPP". This is very odd.
Anyone know how to solve this?
Did you export MYAPP=...? Exporting the variable makes it available to child processes, like java being run by your shell.
In Linux, if you only set the variable (or export it) in a bash session, it will be available to a kind of "sub" session, which is only available to the command you just executed, and nothing else.
You could probably use the dot operator in bash (also called "source" command). From the page:
When a script is run using `source' it runs within the existing shell, any variables created or modified by the script will remain available after the script completes.
So you could try doing . export VARIABLE=value, and then running your java program. This is similar to setting a variable in a Windows terminal, and then opening a new terminal and expecting the env var to be there. It won't.
This way, you are telling bash "this command should be available in this specific session (the session's process)". OTherwise you are telling it "set this env var for the bash session that will end after I run this export command" thus, it won't exist when you run your Java program.
After having defined and exported the environment variable. Launch your IDE from the same Terminal.
Try to write
"$System.env.STOREPWD"
Related
I have set environment variable by executing the command
export test=abcd
I can see test=abcd when I run printenvcommand
I have deployed a springboot.jar application and I am passing the JAVA_OPTS from the springboot.conf file.
JAVA_OPTS='-Dspring.profiles.active=aaa -Denv=$test'
I started the app by service springboot start . When I check the process, env variable doesn't have the value of $test environment variable.
/usr/bin/java -Dsun.misc.URLClassPath.disableJarChecking=true -Dspring.profiles.active=aaa -Denv=.
How can I access the environment variable in the conf file? I read somewhere the environment variables will be stripped off when run as service. Basically I want to run as service springboot start which internally executes the below command
java -Dspring.profiles.active=aws -Denv=${whatever is set for env environment variable} -jar springboot.jar
I have tried the below configurations but nothing worked
JAVA_OPTS='-Dspring.profiles.active=aaa -Denv='$test
JAVA_OPTS='-Dspring.profiles.active=aaa -Denv='${test}
JAVA_OPTS='-Dspring.profiles.active=aaa -Denv=${test}'
JAVA_OPTS="-Dspring.profiles.active=aaa -Denv=$test"
Be careful about your quotes. Assuming that you use a "normal" shell, variables won't be substituted in single quotes.
java -Dspring.profiles.active=aws -Denv="$myvariable" -jar springboot.jar should lead to env being available in the JVM, no matter if you run it as a service or not.
If you can't get it to work, try to specify a hard coded value like this java -Dspring.profiles.active=aws -Denv=foo -jar springboot.jar. If env is now available in the JVM, your problem is with your shell or run mechanism. Verify that the user who runs the command (i.e. do you use sudo?) has the variable set.
I had the same problem where my .conf was referencing an environment variable which was in the .bashrc.
What I found out is:
The problem is service strips all environment variables but TERM, PATH and LANG which is a good thing. If you are executing the script directly nothing removes the environment variables so everything works.
https://unix.stackexchange.com/questions/44370/how-to-make-unix-service-see-environment-variables
One solution would be to install your app as a systemd service:
https://docs.spring.io/spring-boot/docs/1.3.x-SNAPSHOT/reference/html/deployment-install.html
Or another way is to use docker and you can specify extra configuration in the docker file, like loading a file which contains your environment variables.
As those solutions where not available in my case I ended up with having the value in the .conf file, like: -Denv=prod
In Ubuntu I have exported the below environment variable in ~/.bashrc:
export MY_VAR="MY_VAR_VALUE"
When I re-open a terminal I can do:
~ $ echo $MY_VAR
MY_VAR_VALUE
~ $
But when I do this in Java/Eclipse (which I have restarted after exporting the test env. var):
String myVar = System.getenv("MY_VAR");
System.out.println(myVar);
I just get null. Does eclipse not see variables set in ~/.bashrc ?
In Linux (unlike Windows) you need a direct child relatinship between the Java executable, started by Eclipse, started by the Shell where you have exported the variable.
So you must start Eclipse from within that Shell. It wont work if you doubleclick on the executable in desktop or menu.
But I would specify the environment variables you need in the run configuration and not rely on such a setup.
I have noticed that some of my environment variables are not being picked up by the JVM.
In my .bash_profile I defined the following:
IO_HOME='some_value'
export IO_HOME
and by doing in shell:
echo $IO_HOME
I get the correct result.
But neither System.getProperties() nor System.getenv() is showing this variable being set. I tried both Java 6 and Java 7.
Is there something I am missing?
Exporting environment to spawned processes is pretty stable; if System.getenv() is not including a variable then it is because it is not in the environment. A couple of things to check, both relating to how the process is started:
Are you starting the java process from an environment where the variable is exported? For example, if it is in your .bash_profile and you are executing the java program from a menu or desktop then you have to log out and log in after adding it in .bash_profile for your desktop to see the variable.
Is the variable explicitly removed from environment for the process? ProcessBuilder allows this, as do most of all APIs that spawn processes.
One thing to try is to start the process from command line shell, after ensuring the variable is exported in that shell.
From Windows, I recently saw some crazy behaviour where IntelliJ refused to show all env vars from System.getenv() after setting either user or system env vars. The trick was to launch IntelliJ from a DOS box. For Windows users: Maybe a reboot (or logoff/logon) will fix the issue.
Using Java,
How can I add environment variable permanently to the existing env variables.
so that when I do a restart operation for windows or Linux, this environment variable is still there.
You might want to take a look at this.
In Windows you can set a Path Variable from command line so it should do the trick.
I realize this is only applicable to Windows.
Not in any cross platform sort of way. In Linux, these are typically controlled via shell init scripts. You would have to edit one of those (which one depends on the user, system, and shell type). In Windows, this is controlled via system configuration (i'd imagine there are some windows specific APIs to modify those).
coppy the path of jdk upto C:\Program Files\Java\jdk1.6.0\bin from program and past in user variables and put ;.; at the end and give name .
and in system variables click on new and enter the name and past the path....and save ...
go to command prompt
..
to check current paths >echo %path%
to set path >set path="C:\Program Files\Java\jdk1.6.0\bin" enter ok now check and run java program
Environment variables are platform specific. Windows stores them in Registry.
*In the registry the User environment variables are stored at
HKEY_CURRENT_USER\Environment
and the System environment variables are stored at
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment
(from http://demins.blogspot.co.il/2007/10/where-does-windows-xp-store-evrironment.html)*
There are a lot of ways to access windows registry from java. You can for example execute command line using utility named reg that has a reach command line. You can also use one of interoparability APIs like JaWin, Jinterop, Jintegra. You can also refer to my solution explained here.
On linux you can use command line like export MYVAR=myvalue. I mean execute this command line from java using Runtime.exec() or ProcessBuilder. The problem is that this variable will not become really persistent. It will be visiable for all users until the computers is restarted. To make it really persistent you have to modify user login script (e.g. bashrc file for most linux systems if users's default shell is bash).
I've created a stand alone a java application in Ubuntu 10.04 using Netbeans 6.9. I'm not able to use use the getenv() command in Netbeans, though if i create a separate java file in gedit and compile it in the terminal then it gives the desired output.
System.out.println(System.getenv("TRGRAPH"));
The above code when executed through the terminal gives the desired output but the same code if i try to run in Netbeans then it returns a null string.
Can anyone tell me how to get the output using netbeans??
You need to launch Netbeans from the same terminal after you have set and exported TRGRAPH.
Example, in a terminal:
$ export TRGRAPH=foo
$ netbeans&
I use Eclipse, not NetBeans, but I bet they are similar. Look for a dialog that controls how your program gets launched. This dialog probably has a place where you can specify environment variables that should be set when your app is launched.
The other alternative is to set the environment variable before you launch Netbeans.
It means that TRGRAPH is not defined in the process. The environment gets inherited from the environment of Netbeans. Make sure, that Netbeans gets the variable, e.g., by starting it from a command line or by invoking it using a shell script sourcing your .bashrc (or wherever you define TRGRAPH).
Alternatively, you can start an external Java process using the ProcessBuilder and pass it any environment you like. Quite complicated, but very flexible.