7 Configuring Java Delivery

The current release of Oracle GoldenGate Java Delivery requires Java 8. Refer to the section on configuring Java for how to correctly access Java and the required Java shared libraries. Modify the Adapter Properties file to point to the location of the Oracle GoldenGate for Java main JAR (ggjava.jar) and set any additional JVM runtime boot options as required (these are passed directly to the JVM at startup):

jvm.bootoptions=-Djava.class.path=.:ggjava/ggjava.jar -Xmx512m -Xmx64m

Note the following options in particular:

• java.class.path must include pathing to the core application (ggjava/ggjava.jar). The current directory (.) should be included as well in the classpath. Logging initializes when the JVM is loaded therefore the java.class.path variable should including any pathing to logging properties files (such as log4j properties files). The dependency JARs required for logging functionality are included in ggjava.jar and do not need to be explicitly included. Pathing can reference files and directories relative to the Oracle GoldenGate install directory, to allow storing Java property files, Velocity templates and other classpath resources in the dirprm subdirectory. It is also possible to append to the classpath in the Java application properties file. Pathing to handler dependency JARs can be added here as well. However, it is considered to be a better practice to use the gg.classpath variable to include any handler dependencies.

• The jvm.bootoptions property also allows you to control the initial heap size of the JVM (Xms) and the maximum heap size of the JVM (Xmx). Increasing the maximum heap size can improve performance by requiring less frequent garbage collections. Additionally, you may need to increase the maximum heap size if a Java out of memory exception occurs.

Once the properties file is correctly configured for your system, it usually remains unchanged. See Common Properties, for additional configuration options.

Java Delivery is compatible with the Oracle GoldenGate Replicat process. Transaction data is read from the Oracle GoldenGate trail files and delivered to the Oracle GoldenGate Java Delivery module across JNI interface. The data is transferred to the Oracle GoldenGate Java Delivery module using the JNI interface. The Java Delivery module is configurable to allow data to be streamed into various targets. The supported targets for the Oracle GoldenGate Java Adapter product include JMS, file writing, and custom integrations. The Oracle GoldenGate for Big Data product includes all of those integrations and streaming capabilities to Big Data targets.

The Handlers are integrations with target applications which plug into the Oracle GoldenGate Java Delivery module. It is the Java Handlers which provide the functionality to push data to integration targets such as JMS or Big Data applications. The Java Adapter properties file is used to configure Java Delivery and Java handlers. To test the configuration, users may use the built-in file handler. Here are some example properties, followed by explanations of the properties (comment lines start with #):

# the list of active handlers
gg.handlerlist=myhandler
# set properties on 'myhandler'
gg.handler.myhandler.type=file
gg.handler.myhandler.format=tx2xml.vm
gg.handler.myhandler.file=output.xml

This property file declares the following:

• Active event handlers. In the example a single event handler is active, called myhandler. Multiple handlers may be specified, separated by commas. For example: gg.handlerlist=myhandler, yourhandler

• Configuration of the handlers. In the example myhandler is declared to be a file type of handler: gg.handler.myhandler.type=file

  Note:

  See the documentation for each type of handler (for example, the JMS handler or the file writer handler) for the list of valid properties that can be set.

• The format of the output is defined by the Velocity template tx2xml.vm. You may specify your own custom template to define the message format; just specify the path to your template relative to the Java classpath.

This property file is actually a complete example that will write captured transactions to the output file output.xml. Other handler types can be specified using the keywords: jms_text (or jms), jms_map, singlefile (a file that does not roll), and others. Custom handlers can be implemented, in which case the type would be the fully qualified name of the Java class for the handler. Oracle GoldenGate Big Data package also contains built in Big Data target types. For more information, see Integrating Oracle GoldenGate for Big Data.