Application Building Guide

Building Java Applets and Applications

You can develop Java programs to access DB2 databases with the appropriate Java Development Kit (JDK) for your platform. The JDK includes Java Database Connectivity (JDBC), a dynamic SQL API for Java.

DB2 JDBC support is provided as part of the Java Enablement option on DB2 clients and servers. With this support, you can build and run JDBC applications and applets. These contain dynamic SQL only, and use a Java call interface to pass SQL statements to DB2.

DB2 Java embedded SQL (SQLJ) support is provided as part of the DB2 AD Client. With DB2 SQLJ support, in addition to DB2 JDBC support, you can build and run SQLJ applets and applications. These contain static SQL and use embedded SQL statements that are bound to a DB2 database.

The SQLJ support provided by the DB2 AD Client includes:

• The DB2 SQLJ translator, sqlj, which replaces embedded SQL statements in the SQLJ program with Java source statements, and generates a serialized profile which contains information about the SQL operations found in the SQLJ program.
• The DB2 SQLJ profile customizer, db2profc, which precompiles the SQL statements stored in the serialized profile, customizes them into runtime function calls, and generates a package in the DB2 database. For more information on the db2profc command, see the Command Reference.
• The DB2 SQLJ profile printer, db2profp, which prints the contents of a DB2 customized version of a profile in plain text.

To run DB2 Java applications, you must install and invoke a Java Virtual Machine (JVM) that provides native threads support. To execute a Java application using native threads, you can use the -native option in your command. For example, to run the Java sample application, App.class, you can use the following command:

   java -native App

You may be able to specify native threads as the default thread support for some Java Virtual Machines. The information in this chapter assumes native threads support is the default. Please refer to your JVM documentation for instructions on making native threads the default on your system.

To run DB2 Java applets, you may invoke a Java Virtual Machine that provides either native threads or green threads support.

For more information on DB2 programming in Java, refer to the "Programming in Java" chapter in the Application Development Guide.

For the latest, updated DB2 Java information, visit the Web Page at:

   

http://www.ibm.com/software/data/db2/java