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Setting a Java Virtual Machine Parameter when Launching Oxygen JSON Editor

You can set Java Virtual Machine parameters (for example, if you want to increase the maximum amount of memory available) for the Oxygen JSON Editor application launchers or command-line scripts. You can also create a custom startup parameters file.

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Setting Parameters for the Application Launchers

Increasing the Amount of Memory that Oxygen JSON Editor Uses on Windows and Linux

For Windows and Linux installations of Oxygen JSON Editor, the startup launchers for the application and its executable internal tools (Tree Editor, XML Schema Regular Expressions Builder, Large File Viewer, SVN Client, Compare Directories, and Compare Files) include a default .vmoptions file in the installation directory that contains some startup parameters (such the -Xmx parameter, which is used for allocating memory for that particular application). If your installation contains these .vmoptions files, you can edit the parameters in them so that the applications will launch with your desired values. However, if you re-install the application, install an update for the application, or deploy it to other users or machines, those parameters will be reset to their default values.

To increase the memory available to the Oxygen JSON Editor application on Windows:
  1. Browse the installation directory of Oxygen JSON Editor.
  2. Locate the -Xmx parameter in the oxygenJSONEditor26.1.vmoptions file. If it is located in a directory where you do not have write access, copy the file to another folder (where you do have write access), modify it there, and then copy it back to the original location.
    Note: The parameters from the .vmoptions file are used when you start Oxygen JSON Editor with the oxygen launcher (or with the desktop shortcut). If you use the command-line script (<oxygen.bat> or <oxygen.sh>), make sure you use the following procedure instead: Setting Parameters in the Command-Line Scripts.
    Tip: By default, the maximum memory available to the application is about a quarter of the internal memory available on the machine. It is recommended to not use more than half of your existing physical RAM.
  3. Restart Oxygen JSON Editor. Go to Help > About and verify the amount of memory that is actually available (see the JVM Memory Used in the last row in the Copyright tab). If Oxygen JSON Editor does not start and you receive and error message saying that it could not start the JVM, decrease the -Xmx parameter and try again.

Increasing the Amount of Memory that Oxygen JSON Editor Uses on macOS

To increase the memory available to Oxygen JSON Editor on macOS:
  1. Create a file named vmoptions.txt.
  2. Add the -Xmx argument (or other Java VM arguments), one per line, and do not add extra new lines at the beginning or end of the file. For example:
    -Xmx4g
-Dcom.oxygenxml.editor.plugins.dir="$OXYGEN_HOME/plugins"
  3. Make sure you save the file as plain text (in the TextEdit, go to Menu > Format > Make plain text) and copy the file to the Contents folder for the main application launcher. To show the Contents folder for the application launcher, right-click (or Command+Single-Click) the Oxygen JSON Editor icon in Finder, and choose Show Package Contents.

Setting a System Property

Depending on the operating system and type of installer, you can set a Java system property in multiple ways:
  • [Windows/Linux Installer] When installing the application on Windows or Linux using the provided installation kit, you can create your own custom startup parameters file in the installation folder.
  • [macOS Installer] Create a file named vmoptions.txt in the Contents folder within the application installation folder, similarly to this procedure. Add each system property (or Java VM argument) on a separate line. For example:
    -DpropertyName1=value1
-DpropertyName2=value2
  • [Windows Linux/Mac Startup Scripts] The application also contains startup scripts in the installation folder. If you are using such scripts to start the application, you can follow this procedure to set system properties for them: Setting Parameters in the Command-Line Scripts.
Note: You can also set a system property through a parameter prefixed with -Doxy in the command line used to start the application:
oxygen25.1.exe "-Doxyproperty.name=value"
but this system property will be set immediately after the application starts and might not be available if it is needed sooner.

To check the value for a system property, you can select Help > About from the main menu and look in the System properties tab.

To view the list of Oxygen JSON Editor system properties, go to Custom System Properties.

Disabling DPI Scaling

Some users may prefer the look of smaller icons in an HiDPI display. To achieve this, display scaling needs to be disabled for high DPI settings. To disable the DPI scaling, set the following property:
sun.java2d.dpiaware=false

Setting Environment Variables

When started, the application inherits and can access all environment variables set in the operating system. All processes started by the application (for example, publishing using the DITA Open Toolkit engine or starting external tools) also inherit the environment variables provided to the application. Depending on the operating system, environment variables can be set in various ways:
  • [Windows] (Note: You will need Administrator permissions or to work with a system administrator):
    1. Go to Start > Edit the system environment variables > Environment Variables.
    2. Click New in the System variables section.
    3. Specify the variable name and value in the Name and Value fields.
    4. Click OK.
    5. Restart Windows.
  • [Linux]:
    1. Append the following line to the /etc/environment file:

      ENV_VAR_NAME=VALUE

    2. Reboot the computer.
  • [macOS]: There is no standard way to set an environment variable so that it is inherited by the applications regardless of the way they start.

To check the value for an environmental variable, you can select Help > About from the main menu and look in the System properties tab.

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Setting Parameters in the Command-Line Scripts

If you start Oxygen JSON Editor with a command-line script ( oxygenJSONEditor.bat/oxygenJSONEditor.sh ), you have to add or modify parameters in the java command at the end of the script.

For example, to set the maximum amount of Java memory to 2 GB in Windows, add the -Xmx parameter to the last line of the .bat file like this: 

%OXYGEN_JAVA% -Xmx2g -Dsun.java2d.noddraw=true ...

On macOS/Linux, add the -Xmx parameter (followed by a '\') to a new line just above the ro.sync.exml.Oxygen\ line (at approximately line 100) in the .bat file like this: 

-cp "$CP"\
 -Xmx2g\
 ro.sync.exml.Oxygen\
 ..
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Creating Custom Startup Parameters File

You can create your own custom .vmoptions file and the application and the executable tools will automatically include your custom parameters at startup. The following custom files are recognized by the application and the executable tools:
  • custom_commons.vmoptions - The parameters and their values of this file will be included in all the startup launchers.
  • custom_<app name>.vmoptions - The <app name> is the name of the executable application or tool (for example, custom_diffFiles.vmoptions for the Compare Files tool). The parameters and their values of this file will be included in the startup launcher for this particular executable.

For example: To specify a different language for all launchers you can use the custom vmoptions file called custom_commons.vmoptions and the content would look like this:

-Dcom.oxygenxml.language=French
For example: To increase the memory available for a specific tool, such as the Compare Files tool (diffFiles.exe), you can use a custom vmoptions file called custom_diffFiles.vmoptions and the content would look like this:
-Xmx2g

To be recognized and included, these custom startup parameter files must be saved in the installation directory of Oxygen JSON Editor.