Configuring an Instance

This section details how to configure a Payara Micro instance.

Configuring an Instance from the Command Line

As described in Deploying From the Command Line, the starting and configuration of an instance can be done in its entirety on one line.

The options available can be seen by running the JAR with the --help option, or by consulting the Payara Micro Command Line Options section.

The general structure of starting, configuring, and deploying an application to an instance is as follows:

java -jar payara-micro.jar _--option1_ _--option2_ ...

As an example, see below for starting an instance with a non-default HTTP port:

java -jar payara-micro.jar --port 2468

Separating Configuration from Production Run

An instance can be configured separately, but only when persistent root configuration directory is specified by means of command line argument --rootDir.

When switch --warmup is supplied all configuration and deployment command line parameters are applied to configuration directory and the instance immediately shuts down:

java -jar payara-micro.jar --option1 --option2 deployment.war --warmup

Another use case for --warmup is to collect profiling information for e.g. Class Data Sharing feature of JDK:

# Open JDK 11; launcher needs to be used because of simpler classpath
java -XX:DumpLoadedClassList=classes.lst -jar rootidr/launch-micro.jar  --warmup

# OpenJ9
java -Xshareclasses:name=payara-micro -jar payara-micro.jar --warmup

Read configuration from a file

With --domainConfig option, it is possible to define multiple options in a configuration file. This option would override the default Payara Micro configuration completely. The provided file must conform to the same structure as the domain.xml file in a Payara Server domain.

The --rootDir option sets the root configuration directory and saves the configuration across restarts. If empty, this directory will be filled by the default configuration, including the domain.xml file.


If specifying multiple options at once, the following precedence is followed:

rootDir < domainConfig < autoBindHttp | autoBindSsl < port | sslPort

In human language:

  • The domain.xml in the directory specified by the rootDir option (if one exists) is overridden by the domain.xml specified with the domainConfig option

  • The HTTP and HTTPS port numbers specified in either of these domain.xml files are overridden to be the default values of 8080 and 8081 when the autoBindHttp or autoBindSsl options are enabled respectively.

  • These default port values are then overridden in turn by the port numbers specified with the port or sslPort options.

Configuring an Instance Programmatically

There are various methods available for configuring a Payara Micro instance programmatically. You can only configure an instance before it is bootstrapped however.

The configuration methods available to you should be detected by your IDE, allowing you to view them using the auto-complete feature common to most popular IDEs. Alternatively, you can consult the Payara Micro Configuration Methods section.

As noted in the Deploying an Application Programmatically section, you can either call the desired configuration commands on one line during instance initialization, or on separate lines after creating a PayaraMicro variable.

As an example of configuring an instance to use a different HTTP and Cluster start port on one line, see here:

import fish.payara.micro.BootstrapException;
import fish.payara.micro.PayaraMicro;

public class EmbeddedPayara{
    public static void main(String[] args) throws BootstrapException{

For the example of the same, but done across multiple lines, see here:

import fish.payara.micro.BootstrapException;
import fish.payara.micro.PayaraMicro;

public class EmbeddedPayara{
    public static void main(String[] args) throws BootstrapException{
        PayaraMicro micro = PayaraMicro.getInstance();

It is also possible to configure an instance programmatically by specifying a domain.xml file that is packaged within your application by passing a resource string to the setApplicationDomainXML method. The path in the string will be resolved using the getResource method of the thread context class loader:

import fish.payara.micro.BootstrapException;
import fish.payara.micro.PayaraMicro;

public class EmbeddedPayara{
    public static void main(String[] args) throws BootstrapException{

Packaging a Configured Instance as an Uber Jar

Sometimes it is preferable to package the application (or applications), configuration and dependencies into a single executable jar. To do this with Payara Micro use the --outputUberJar command line option as in this example:

java -jar payara-micro.jar --deploy test.war --outputUberJar test.jar

This will package up the payara-micro.jar and the WAR application into a single JAR. The resulting file can be executed like this:

java -jar test.jar

Any additional command line options you specify when creating an Uber JAR are recorded, so the Payara Micro instance is configured later when executing the packaged JAR:

java -jar payara-micro.jar --deploy test.war --port 9080 --lite --clusterName test-cluster --clusterPassword test-password --outputUberJar test2.jar
All specified command line option will be retained when the Uber JAR is executed.

Uber JAR Context Root

When creating an Uber JAR, the context root of the packaged application will always be the name of the application WAR that is deployed. For example, the test.war that was packaged into the test2.jar on port 9080 would be accessible on the following path:


Currently, this is always the case; including when a context root is specified in a glassfish-web.xml deployment descriptor.

If the WAR file is renamed to ROOT.war and packaged as an Uber JAR, it will be deployed to the root context:

java -jar payara-micro.jar --deploy ROOT.war --port 9080 --outputUberJar test3.jar
java -jar test3.jar

The application will now be accessible on:


Package Additional Files

It’s also possible to package additional files into an Uber JAR, by using a custom root directory. You can run a Payara Micro instance first by generating the domain directory first using the --rootDir option first:

java -jar payara-micro.jar --rootDir /tmp/micro-dir/

You can then add files to the root directory like this:

> cd /tmp/micro-dir/
> ls -lsarth

total 784K
   0 drwxr-xr-x 1 root 197609    0 Mar 24 18:16 docroot
160K -rw-r--r-- 1 root 197609 158K Mar 24 18:16 __ds_jdbc_ra.rar
   0 drwxr-xr-x 1 root 197609    0 Mar 24 18:16 META-INF
160K -rw-r--r-- 1 root 197609 159K Mar 24 18:16 __cp_jdbc_ra.rar
160K -rw-r--r-- 1 root 197609 159K Mar 24 18:16 __xa_jdbc_ra.rar
160K -rw-r--r-- 1 root 197609 160K Mar 24 18:16 __dm_jdbc_ra.rar
   0 drwxr-xr-x 1 root 197609    0 Mar 24 18:17 autodeploy
   0 drwxr-xr-x 1 root 197609    0 Mar 24 18:20 lib
4.0K drwxr-xr-x 1 root 197609    0 Mar 30 19:22 config
128K drwxr-xr-x 1 root 197609    0 Mar 30 19:23 runtime

> cp ~/test-properties /tmp/micro-dir/config/.

And then, generate the Uber JAR using the modified root directory:

java -jar payara-micro.jar --rootDir /tmp/micro-dir/ --outputUberJar custom-micro.jar

You can verify that the files are located in the MICRO-INF/ directory:

> unzip -d custom-micro custom-micro.jar
> ls -lsarth custom-micro/** | grep

total 304K
1.0K -rw-r--r-- 1 fabio 197609   24 Apr  3 20:26
Additional JAR files that are placed in the ${PAYARA_INSTALL_DIR}/lib directory will be ignored when being packaged to the Uber JAR. To package additional JAR files into an Uber JAR, check the Adding Third Party JARs section

Configuring Payara Micro via System Properties and Environment Variables

Payara Micro can also be configured via system properties. These can either be set on the command line or passed into Payara Micro using the --systemProperties command line option which will load the properties from the specified file.

Payara Micro can also be configured using Environment variables. The environment variables supported are the same as the system properties below just replace the . with _ for example payaramicro.port should be payaramicro_port when used as a system property.

Payara Micro supports the following system properties:

System Property Equivalent Command Line Flag


































































Configuring Alternate KeyStores for SSL

Payara Micro comes with Keystore files directly embedded within the JAR file.

These can be overridden using the following standard Java SSL system properties:





When packaging applications into an Uber Jar any keystores specified via system properties will be copied into the uber JAR to replace the default internal keystores. However the uber JAR will not contain the passwords and these must still be specified via the system properties.
asadmin commands like add-pkcs8 and add-to-keystore are NOT supported in pre-boot and post-boot commands with Payara Micro and Java SSL system properties need to be used to point to the correct stores.

Setting the Key-Pair at Runtime

The key-pair to use as Payara Micro’s SSL certificate can also be specified using the --sslCert command line option like this:

java -jar payara-micro.jar -sslCert my-custom-alias
The default key-pair name is s1as if not overridden via the command line switch.

Payara Micro Instance Names

Payara Micro instances are automatically assigned a name on boot. These names are generated from a dictionary of adjectives and fish names as adjective-fish. For example: Magnanimous-Payara, Disgruntled-Goldfish, and Bamboozled-Tetra.

Setting a Custom Instance Name

Instance names can be overridden with the --name command-line argument on start-up. Manually entered instances names are non-unique.

As an example, see below:

java -jar payara-micro.jar --name MicroInstance1