How to set system property?

I am trying to follow this instruction for running gate embedded.

It says: "System property gate.home should be set to the gate installation directory." (http://gate.ac.uk/wiki/code-repository/)

How do I do this?

Also when I try to run the example code of EmbeddedAnnie I get the following error: ( I don't know if it is related or not ).

Initialising GATE...
GATE home system property ("gate.home") not set.
Attempting to guess...
Using "C:\Program Files (x86)\GATE-6.0" as GATE Home.
If this is no开发者_如何学运维t correct please set it manually using the -Dgate.home option in yo
ur start-up script
Using C:\Program Files (x86)\GATE-6.0 as GATE home
Using C:\Program Files (x86)\GATE-6.0\plugins as installed plug-ins directory.
Using C:\Program Files (x86)\GATE-6.0\gate.xml as site configuration file.
Using C:\Users\UNST\gate.xml as user configuration file
Using C:\Users\UNST\gate.session as user session file
Exception in thread "main" java.lang.NoClassDefFoundError: gate/creole/gazetteer
/AbstractGazetteer
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:616)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:14
1)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
        at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
        at sun.misc.Launcher$ExtClassLoader.findClass(Launcher.java:229)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:296)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:296)
        at gate.util.GateClassLoader.loadClass(GateClassLoader.java:63)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
        at gate.creole.CreoleAnnotationHandler.processAnnotationsForResource(Cre
oleAnnotationHandler.java:193)
        at gate.creole.CreoleAnnotationHandler.processAnnotations(CreoleAnnotati
onHandler.java:169)
        at gate.creole.CreoleAnnotationHandler.processAnnotations(CreoleAnnotati
onHandler.java:173)
        at gate.creole.CreoleAnnotationHandler.processAnnotations(CreoleAnnotati
onHandler.java:173)
        at gate.creole.CreoleAnnotationHandler.processAnnotations(CreoleAnnotati
onHandler.java:157)
        at gate.creole.CreoleRegisterImpl.processFullCreoleXmlTree(CreoleRegiste
rImpl.java:358)
        at gate.creole.CreoleRegisterImpl.parseDirectory(CreoleRegisterImpl.java
:341)
        at gate.creole.CreoleRegisterImpl.registerDirectories(CreoleRegisterImpl
.java:306)
        at gate.Gate.initCreoleRepositories(Gate.java:449)
        at gate.Gate.init(Gate.java:230)
        at StandAloneAnnie.main(StandAloneAnnie.java:69)
Caused by: java.lang.ClassNotFoundException: gate.creole.gazetteer.AbstractGazet
teer
        at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
        at sun.misc.Launcher$ExtClassLoader.findClass(Launcher.java:229)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
        ... 27 more

You can do this via a couple ways.

One is when you run your application, you can pass it a flag.

java -Dgate.home="http://gate.ac.uk/wiki/code-repository" your_application

Or set it programmatically in code before the piece of code that needs this property set. Java keeps a Properties object for System wide configuration.

Properties props = System.getProperties();
props.setProperty("gate.home", "http://gate.ac.uk/wiki/code-repository");

System.setProperty("gate.home", "/some/directory");

For more information, see:

• The System Properties tutorial.
• Class doc for System.setProperty( String key , String value ).

System.setProperty("gate.home", "/some/directory"); 

After that you can retrieve its value later by calling

String value =  System.getProperty("gate.home");

For JBoss, in standalone.xml, put after .

<extensions>
</extensions>

<system-properties>
    <property name="my.project.dir" value="/home/francesco" />
</system-properties>

For eclipse:

http://www.avajava.com/tutorials/lessons/how-do-i-set-system-properties.html?page=2

You need the path of the plugins directory of your local GATE install. So if Gate is installed in "/home/user/GATE_Developer_8.1", the code looks like this:

System.setProperty("gate.home", "/home/user/GATE_Developer_8.1/plugins");

You don't have to set gate.home from the command line. You can set it in your application, as long as you set it BEFORE you call Gate.init().