12 Java in the Database

Installation of a Java Enabled Database

Since Oracle8i, for the first time, Oracle is using POSIX interfaces. This does not mean that Oracle 'is running in POSIX' but that a few POSIX APIs are used by Oracle. Whereas, the overwhelming majority of APIs is still native BS2000. For example, PAM calls, common memory pools, sockets, and so on. However, the POSIX part of Oracle must be installed.

The procedure INSTALL.P.POSIX copies two special files, classes.bin and libcorejava.so, into the specified POSIX directory and changes the value of ORACLE_HOME in $ORAC1020.DEMO.P.ORAENV.

When you call $ORAC1020.INSTALL.P.SUPER and set the JAVA parameter to YES, you'll get a suitable ORAENV file (with ORACLE_HOME as described earlier), a database sized to Java requirements and Java installed inside the database.

When you try to enable Java an existing Oracle Database 10g, you can use the Java related parts of this procedure as an example and modify it according to your needs, that is, increase dbsize, increase shared_pool_size, create a large rollback segment, run initjvm.sql, and so on. For more information, refer to Oracle Database Java Developer's Guide.

After successful installation, when you get the following message you should ask the BS2000 administrator to increase the number of UFS devices by modifying the parameter NOSTTY in the configuration file SYSSSI.POSIX-BC.version.

CCM0090: ALL UFS TERMINAL DEVICES ARE IN USE OR PERMISSION DENIED

Where can files related to Java reside and how should they be encoded?

It is not absolutely straightforward where files used by Java have to be stored and how they should be encoded. In general files can reside in native BS2000 or in the POSIX file system, but there are exceptions.

The following table gives an overview of the file types, location, default encoding, and encoding modifications for APIs or statements

BS2000 PAM files in ascii can be created by transferring files (ftp) from an ascii platform to BS2000 in binary mode.

The distinction between a native BS2000 file name and a POSIX file name is made by the preceding slash ('/'). As a consequence, no relative path names are allowed for POSIX file names.

However, there is one exception: when used within dbms_java.loadjava, relative path names are preceded by the value of ORACLE_HOME in ORAENV file.

Database character sets and Java Encodings

As far as I/O is concerned, the Oracle JAVAVM uses the database character set as system property file.encoding. Therefore the following Oracle/BS2000 database character sets have been added to the list of supported Java encodings:

WE8BS2000
WE8BS2000E
EE8BS2000
CE8BS2000
CL8BS2000
WE8BS2000L5

These encodings are not known to any other Java implementation.

The system property file.encoding, however, does not apply to Java property files. Property files always use the encoding 8859_1 (refer to Oracle Database SQLJ Developer's Guide and Reference). The system property file.encoding is used when compiling a source file. You can change this default by either using the following procedure or by setting the encoding option of the procedure dbms_java.loadjava:

dbms_java.set_compiler_option('','encoding',...)

Loadjava

This utility is not available on BS2000. However, you can use the dbms_java.loadjava (resp.dropjava) package, within SQL*Plus, which is almost as capable as the loadjava utility. For more information, refer to Oracle Database Java Developer's Guide).

You can use the loadjava utility from a Unix or Windows platform to load Java objects into a BS2000 Oracle Database 10g.

Java Demonstration Files

A simple Java demonstration program running in the server is shipped under:

$ORAC1020.JAVAVM.DEMO.HELLO.SQL

An example with database connection using the server-side internal driver is shipped under:

$ORAC1020.JAVAVM.DEMO.EMPLOYEE*

Restrictions

Native Compilation using Accelerator is not supported.