Help needed calling a java file

[rfresh]

I had Tom Cat Java installed on my Linux sever and I need to call a java file, which isn't working. Someone told me to verify Java is in fact installed on my server using this command:

 

echo exec('which java');

 

but when I run it, nothing displays!

 

The java command I'm trying to run is this:

 

exec('java -Xmx1024m -jar "/home/account/public_html/java -cp b4a_c2dm.jar anywheresoftware.b4a.c2dm.C2DM send  $php_device_id \"test\""');

 

The .jar file is there.

 

My path to java is: /usr/local/jdk/bin/java

 

Thanks for any help...