Java support
You must deploy the PowerBuilder pbjvm100.dll file
with any applications or components that use the Java Runtime Environment
(JRE), and there must be a JRE installed on the target computer.
The JRE is required for JSP targets, EJB clients, JDBC connections,
and saving as PDF using XSL-FO. You can copy the JRE installed with
PowerBuilder to the same directory as the PowerBuilder runtime files
on the target computer, or use an existing JRE whose location is defined
in the user’s system PATH environment variable.
Locating the Java VM
When a PowerBuilder application requires a Java VM, the PowerBuilder runtime
searches for the jvm.dll file in a subdirectory
of the directory where pbjvm100.dll is installed
on the user’s computer. The jvm.dll file
is installed in the JREinclient directory
of JDK 1.4 installations, and in the JREinclassic directory
in JDK 1.2 and 1.3 installations.
PowerBuilder adds the location of jvm.dll to
the beginning of the path currently being used by the PowerBuilder
application. This path is a copy of the path defined in the user’s
PATH system environment variable. PowerBuilder does not modify
the environment variable maintained in the Windows registry.
To locate the jvm.dll, PowerBuilder first
determines where pbjvm100.dll is installed.
Suppose pbjvm100.dll is installed in C:SybaseSharedPowerBuilder.
Then PowerBuilder uses this search procedure to add the location
of the jvm.dll to the path currently in use:
- Search for the directory structure JREinclient (for
JDK 1.4) in C:SybaseSharedPowerBuilder and,
if found, add it to the beginning of the path. - If not found, search for the directory structure JDK14JREinclient in C:SybaseSharedPowerBuilder and,
if found, add it to the beginning of the path. - If not found, search for the directory structure JREinclassic (for
JDK 1.2 or 1.3) in C:SybaseSharedPowerBuilder and,
if found, add it to the beginning of the path.
If none of these directory structures is found, PowerBuilder
uses the first jvm.dll whose location is defined
in the user’s PATH environment variable. If no jvm.dll is
found, the Java VM does not start.
The runtime Java VM classpath
When PowerBuilder starts a Java VM, the Java VM uses internal
path and class path information to ensure that required Java classes
are always available. At runtime, the Java VM uses a class path
constructed by concatenating these paths:
- The
system JAVA_HOME environment variable. - A class path added programmatically when the Java
VM is started. For example, EJB client applications can pass a class
path to the CreateJavaVM method. - The PowerBuilder runtime static registry class path.
This is a path built into the pbjvm100.dll file that
corresponds to the path in the Windows Registry that is used when
you are developing an application in PowerBuilder. It contains classes
required at runtime for features that use a Java VM. - The system CLASSPATH environment variable.
- The current directory.
Overriding the runtime static registry classpath
If necessary, you can override the JVM settings and properties
defined for runtime use in the static registry. PowerBuilder uses
the following algorithm to locate configuration information:
- When the first request is made
for a JVM, PowerBuilder looks for registry entries for the configuration
information and properties to be passed to the function that creates
the JVM. - If PowerBuilder finds a registry entry for the configuration
information, it uses it instead of the static registry. If it does
not find a registry entry, it uses the static registry. - If PowerBuilder finds a registry entry for custom
properties to be passed to the JVM, it uses those instead of the
static registry. If it does not find a registry entry, it uses the
static registry entries.
To override the
default settings, create a new key named PBRTConfig in
the HKEY_LOCAL_MACHINESoftwareSybasePowerBuilder10.0Java key, then
add either or both of the following subkeys: PBJVMconfig and PBJVMprops.
To duplicate the static registry entries, add the same string
values to these subkeys that you see in the PBIDEConfig key, that
is:
| Subkey | String value name | String value data |
|---|---|---|
| PBJVMconfig | Count | 1 |
| 0 | -verbose:jni,class | |
| PBJVMprops | java.compiler | NONE |
You can override either the configuration or properties entries
or both. If you make incorrect entries, PowerBuilder attempts to
recover by defaulting to the static registry. However, you should
be cautious about making any changes since you can cause incorrect
behavior in the JVM if you do not configure it correctly.