Why and when to perform this task
You can make various changes to applications and their contents without having to stop the server and start it again. Making these types of changes is known as hot deployment and dynamic reloading.Hot deployment is the process of adding new components (such as WAR files, EJB Jar files, enterprise Java beans, servlets, and JSP files) to a running server without having to stop the application server process and start it again.
Dynamic reloading is the ability to change an existing component without needing to restart the server in order for the change to take effect. Dynamic reloading involves:
If the application you are updating is deployed on a server that has its application class loader policy set to Single, you might not be able to dynamically reload your application. At minimum, you must restart the server after updating your application.
CAUTION: Do not use hot deployment to update components in a production deployment manager managed cell. Hot deployment is well-suited for development and testing, but poses unacceptable risks to production environments. Full or partial resynchronization might erase hot deployed components. Also, running the restoreconfig command might overwrite changes made to expanded application files. Further, hot deployed components are not migrated between versions of WebSphere Application Server. To add new components or modules to an enterprise application, reassemble the application EAR file so it has the new components or modules and then redeploy the EAR file.
Steps for this task
It is important to locate the expanded application files because, as part of installing applications, a WebSphere application server unjars portions of the EAR file onto the file system of the computer that will run the application. These expanded files are what the server looks at when running your application.
If you cannot locate the expanded application files, look at the binariesURL attribute in the deployment.xml file for your application. The attribute designates the location the run time uses to find the application files.
For the remainder of this information on hot deployment and dynamic reloading, application_root represents the root directory of the expanded application files.
Metadata XML files for an application can be loaded from one of two locations. The metadata files can be loaded from the same location as the application binary files (such as application_root/META-INF) or they can be loaded from the WebSphere configuration tree, ${CONFIG_ROOT}/cells/cell_name/applications /application_EAR_name/deployments/application_name/. The value of the useMetadataFromBinary flag specified during application installation controls which location is used. If specified, the metadata files are loaded from the same location as the application binary files. If not specified, the metadata files are loaded from the application deployment folder in the configuration tree.
For the remainder of this information, metadata_root represents the location of the metadata files for the specified application or module.
Results
The application files are updated on the server.Because you directly manipulated the application files on the server, you might not be able to later use the administrative console or a wsadmin scripting command to work with the files. For example, if you try exporting a manually changed application using Export on an Enterprise Applications console page, your manual changes to an application in the installedApps directory are not exported. To export those changes, you must copy and move the application files manually.