# Running from a Jar file
# Installing Java
Atsumeru requires installed Java version 8+ (1.8+). Both Oracle Java (opens new window) and OpenJDK (opens new window) are suitable
To find out if Java is installed and its version, use command java -version
Install Java for your system:
# Windows
Download and install the installation kit from Oracle (opens new window)/OpenJDK (opens new window)
# Linux/MacOS
Download OpenJDK (opens new window) from repository or install it manually from deb/rpm/tar.gz package
Often current Linux systems come with OpenJDK 11+ and no additional installation is required
# Launching
You can run Atsumeru from a standalone jar file. The actual version can be downloaded from Releases (opens new window) section in GitHub repository
To start server you can use following command (replace x.y.z with the version of downloaded file)
java -jar Atsumeru-x.y.z.jar
On Windows systems you can use javaw instead of java to start server without displaying command line window
On Windows systems it is sometimes necessary to Unlock jar file in its properties after downloading
Once started, server will be available for management from Atsumeru Manager (opens new window) 
and read from supported applications (e.g., Atsumeru (opens new window)
The first startup is accompanied by creation of necessary files (cache, settings, databases) next to a jar file. Also, an Admin user is created with a random password, which will be displayed once in the console. It is recommended to change this password and/or create a new Administrator by removing default one
To create a new Admin user, just stop server, delete database at /database/users.db and start server
This operation deletes all previously created users, so it is not recommended to perform it if there are any
# Increasing memory limits
The server will consume not much RAM even with large libraries. Change the memory limits only as a last resort when the server explicitly errors that it is not enough, otherwise you might run into all sorts of problems if you specify this parameter incorrectly!
By default, java' process gets a limited maximum amount of RAM it can use while running. Often, this is~1 GB'. If there are problems with server, or if errors like OutOfMemoryException appear in the console/logs, you probably need to increase maximum amount of memory that Atsumeru can use
To do this, add -Xmx<size> flag to server start command, where <size> can be any value of type 2048m (Megabytes), 3g (Gigabytes) and so on. For example, to start a server using up to 3GB of memory, you would use following command:
java -jar -Xmx3072m Atsumeru-x.y.z.jar
or
java -jar -Xmx3g Atsumeru-x.y.z.jar
# Updating
To update server it must be stopped and restarted using the latest jar version