Linux command to get current value of java.io.tmpdir

Question

I need a Linux command to get current value of java.io.tmpdir Also can you tell me the command to get all the system propeties.

Shaveling

do you mean environment variables by "system properties"? – Lemon

Answer 1

JDK provides tools with which you can achieve your goal. Using the specified command, you can display the value of a system variable java.io.tmpdir.

jinfo <process id> | grep "java.io.tmpdir"

The <process id> is the number of the java process for which you want to display the value of the system variable. Id of the java process you can get by using the jps tool, which list all java processes running on your machine.

To see all system variables of the java process, please use this command

 jinfo <process id>

All JDK tools are located in $JAVA_HOME/bin directory.

java.io.tmpdir is one of java system properties, so its value exists only inside jvm. To find out what is the value of java.io.tmpdir property you can also write a simple program in java. It may look something like this piece of code:

public class JSystemProperties {
    public static void main(String[] args) {
        System.getProperties().list(System.out);
    }
}

The code above will print all java system properties, but you can modify this to print only one system property with name you pass through args array (using System.getProperty(key) method). After you compile this class you can create script (which will run compiled java class) that can be treated as Linux command to get current values of java system properties.

Mystic

Error attaching to process: sun.jvm.hotspot.debugger.DebuggerException: Can't attach to the process – Oakum

try to switch to root user or to the same user who started JVM – Mystic

This program required import java.util.Properties. I think it make sense to edit this to System.getProperties().list(System.out); – Schlessel

Answer 2

For black box Java applications I've deployed in the past, I have sometimes been able to find the value of java.io.tmpdir by executing the following command:

ps -ef | grep java.io.tmpdir

Particularly with tomcat apps, you may get an output like this:

-Djava.io.tmpdir=/usr/local/tomcat/temp

Ignatzia

Answer 3

For temp dir: there is a good answer here.

For all environment variable, try env command.

Lemon

Answer 4

Run:

java -XshowSettings

and look for the value of "java.io.tmpdir ="

Property settings:
file.encoding = UTF-8
file.separator = /
java.class.path = 
java.class.version = 61.0
java.home = /usr/lib/jvm/zulu17-ca
java.io.tmpdir = /tmp  # <---- HERE

Capital

Answer 5

Recommended tool now is jcmd, use it like :

jcmd $pid VM.system_properties | grep java.io.tmpdir

Komsomolsk