Run an embeddable container

Use this task to run an embeddable container. Applications running in the embeddable container start faster and require a smaller footprint than when running in the full application server. It is an ideal environment for quickly developing and testing applications that might eventually run in the application server.

Before running an embeddable container, we must have the following items ready:

• A copy of the <app_server_root>\runtimes\com.ibm.ws.ejb.embeddableContainer_9.0.jar

  Restriction: The EJB thin client, com.ibm.ws.ejb.thinclient_9.0.jar, and the EJB embeddable JAR file, com.ibm.ws.ejb.embeddableContainer_9.0.jar, cannot coexist in the same class path.

• A copy of the <app_server_root>\runtimes\endorsed\endorsed_apis_9.0.jar file, if we are using the @Resource annotation with the lookup attribute

• One or more EJB modules in JAR files or class directories
• A main class that creates the embeddable container
• A Java SE Development Kit (JDK) or a Java Runtime Environment (JRE) v8.0 or later

The key to running the embeddable container is the class path. The class path must include all the artifacts previously listed. For example, if the main class is my.pkg.MyMainClass, and it uses enterprise beans stored in the MyEJBModule.jar file, the following line might run the main class that launches the embeddable container. This example assumes that all JAR files and class directories are in the current working directory.

• Windows:

  C:\test> java -cp .;com.ibm.ws.ejb.embeddableContainer_9.0.jar my.pkg.MyMainClass
  

• UNIX:

  [test]$ java -cp .:com.ibm.ws.ejb.embeddableContainer_9.0.jar:MyEJBModule.jar my.pkg.MyMainClass
  

It is possible to run the embeddable container without specifying all the modules on the class path. This requires the code to specify a File or File array for the MODULES property, and the context class loader for the thread creating the container instance must be able to load the specified files.

To specify embeddable container properties in a text file other than embeddable.properties in the current working directory, then specify the com.ibm.websphere.embeddable.configFileName system property; for example:

• Windows:

  C:\test> java -Dcom.ibm.websphere.embeddable.configFileName="C:\test\my-config.properties"
   -cp .;com.ibm.ws.ejb.embeddableContainer_9.0.jar;MyEJBModule.jar my.pkg.MyMainClass
  

• UNIX:

  [test]$ java -Dcom.ibm.websphere.embeddable.configFileName="/home/myusername/test/my-config.properties"
   -cp .:com.ibm.ws.ejb.embeddableContainer_9.0.jar:MyEJBModule.jar my.pkg.MyMainClass
  

When we are developing an application that uses JPA in the embeddable EJB container, the class path must include the JPA thin client, com.ibm.ws.jpa-2.1.thinclient_9.0.jar. The JPA thin client is located in \runtimes where the root directory of the installation image is located.

• Windows:

  C:\test> java -cp .;com.ibm.ws.ejb.embeddableContainer_9.0.jar;%WAS_HOME%\runtimes
    \com.ibm.ws.jpa-2.1.thinclient_9.0.jar;MyEJBModule.jar my.pkg.MyMainClass
  

• UNIX:

  [test]$ java -cp .:com.ibm.ws.ejb.embeddableContainer_9.0.jar:${WAS_HOME}/runtimes
    /com.ibm.ws.jpa-2.1.thinclient_9.0.jar:MyEJBModule.jar my.pkg.MyMainClass
  

Because JPA providers differ in both behavior and vendor-specific APIs, for applications dependent on OpenJPA, the JPA 2.0 thin client can instead be used with the EJB Embeddable Container. Include the JPA 2.0 thin client located in the directory {WAS_INSTALL_ROOT}\runtimes\com.ibm.ws.jpa-2.0.thinclient_9.0.jar.

We can specify the Java agent mechanism to complete the dynamic enhancement at run time. For example, type the following line of code at the command prompt:

• Windows:

  C:\test> java -javaagent:%WAS_HOME%\runtimes\com.ibm.ws.jpa-2.1.thinclient_9.0.jar
   -cp .;com.ibm.ws.ejb.embeddableContainer_9.0.jar;MyEJBModule.jar my.pkg.MyMainClass
  

• UNIX:

  [test]$ java -javaagent:${WAS_HOME}/runtimes/com.ibm.ws.jpa-2.1.thinclient_9.0.jar
   -cp .:com.ibm.ws.ejb.embeddableContainer_9.0.jar:MyEJBModule.jar my.pkg.MyMainClass
  

To enable tracing in the embeddable container, we can specify the com.ibm.ejs.ras.lite.traceSpecification system property to a trace specification value as we would specify for the server. By default, the trace is printed to standard output, but we can redirect the output by specifying the com.ibm.ejs.ras.lite.traceFileName system property. The following example shows how we can use both system properties:

• Windows:

  C:\test> java -Dcom.ibm.ejs.ras.lite.traceSpecification=EJBContainer=all:MetaData=all
   -Dcom.ibm.ejs.ras.lite.traceFileName=trace.log
   -cp .;com.ibm.ws.ejb.embeddableContainer_9.0.jar;MyEJBModule.jar my.pkg.MyMainClass
  

• UNIX:

  [test]$ java -Dcom.ibm.ejs.ras.lite.traceSpecification=EJBContainer=all:MetaData=all
   -Dcom.ibm.ejs.ras.lite.traceFileName=trace.log
   -cp .:com.ibm.ws.ejb.embeddableContainer_9.0.jar:MyEJBModule.jar my.pkg.MyMainClass
  

If our beans use the javax.annotation.Resource annotation with the lookup attribute, we must also use the Java Endorsed Standards Override Mechanism to override the javax.annotation.Resource API that is available in the JDK on the system. Copy the app_server_root\runtimes\endorsed\endorsed_apis_9.0.jar file into a target directory of our choice. Use the java.endorsed.dirs property on the Java command to specify your directory containing the copied JAR file. The following example shows how we can specify the java.endorsed.dirs property:

• Windows:

  C:\test> java -Djava.endorsed.dirs="myTargetDirectory"
   -cp .;com.ibm.ws.ejb.embeddableContainer_9.0.jar;MyEJBModule.jar my.pkg.MyMainClass
  

• UNIX:

  [test]$ java -Djava.endorsed.dirs="myTargetDirectory"
   -cp .:com.ibm.ws.ejb.embeddableContainer_9.0.jar:MyEJBModule.jar my.pkg.MyMainClass
  

Related:

Trace user interface for stand-alone clients

Use bean validation in the product