View source for Documentation/DevGuide/WritingUNO/The Java Environment in Apache OpenOffice

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{{DISPLAYTITLE:The Java Environment in Apache OpenOffice}}
When UNO components written in Java are to be used within the office suite, the office suite has to be configured to use the appropriate JRE. For information on the supported JREs see [[Documentation/FAQ/Installation/Which version of Java do I need%3F]].

== {{AOo}} ==
Since the release of {{AOo}} 3.4.0 you can set the JRE from the menu '''Tools->Options''' : tree node '''OpenOffice->Java'''.

== {{PRODUCTNAME}} {{OOo2.x}} ==
In {{PRODUCTNAME}} {{OOo2.x}} there is no ''java(.ini|rc)'' anymore. All basic Java settings are set in the options dialog: tree node {{PRODUCTNAME}}->Java. The Parameters dialog can be used to specify the debug options and other arguments. 

For applets there are still a few settings on the security panel (tree node {{PRODUCTNAME}}->Security).

== Versions prior to {{PRODUCTNAME}} {{OOo2.x}} ==

Prior to {{PRODUCTNAME}} {{OOo2.x}}, this configuration happened during the installation, when the Java setup was performed. Then, a user could choose a Java Runtime Environment or choose to install a JRE. After installing the office, the selected JRE could still be changed with the ''jvmsetup'' program, which was located in the program folder. The data for running the Java Virtual Machine was stored in the ''java(.ini|rc)'' file and other configuration files. 

{{Note|The ''java(.ini<nowiki>|</nowiki>rc)'' actually is an implementation detail. Unfortunately, it needs to be modified under some rare circumstances, for example for debugging purposes. You must not rely on the existence of the file nor should you make assumptions about its contents.}}

In an office with a lower version than {{OOo2.x}}, the ''java(.ini|rc)'' is located in the ''<officepath>\user\config'' directory. A client can use that file to pass additional properties to the Java Virtual Machine, which are then available as system properties. For example, to pass the property <code>MyAge</code>, invoke Java like this:

  java -DMyAge=30 RunClass 

If you want to have that system property accessible by your Java component you can put that property into ''java(ini|rc)'' within the <code>[Java]</code> section. For example:

  [Java]
  Home=file:///C:/Program%20Files/Java/j2re1.4.2
  
  VMType=JRE
  Version=1.4.2
  RuntimeLib=file:///C:/Program%20Files/Java/j2re1.4.2/bin/client/jvm.dll
  SystemClasspath=d:\645m15\program\classes\classes.jar;; ...
  Java=1
  JavaScript=1
  Applets=1 
  MyAge=27

To debug a Java component, it is necessary to start the JVM with additional parameters. The parameters can be put in the ''java.ini'' the same way as they would appear on the command-line. For example, add those lines to the <code>[Java]</code> section:

  -Xdebug
  -Xrunjdwp:transport=dt_socket,server=y,address=8000

More about debugging can be found in the JDK documentation and in the {{PRODUCTNAME}} Software Development Kit.

Java components are also affected by the following configuration settings. They can be changed in the '''Tools - Options''' dialog. In the dialog, expand the {{PRODUCTNAME}} node on the left-hand side and choose '''Security'''. This brings up a new pane on the right-hand side that allows Java specific settings:

{|border="1" cellpadding=4 style="border-collapse:collapse;"
|-bgcolor=#EDEDED
!Java Setting 
!Description 
|-
|Enable 
|If checked, Java is used with the office. This affects Java components, as well as applets. 
|-
|Security checks 
|If checked, the security manager restricts resource access of applets. 
|-
|Net access 
|Determines where an applet can connect.  
|-
|ClassPath 
|Additional jar files and directories where the JVM should search for classes. Also known as user classpath. 
|-
|Applets 
|If checked, applets are executed. 
|}

{{PDL1}}

[[Category:Documentation/Developer's Guide/Writing UNO Components]]