Set variable not working

[andres digiovanni, módosítva 11 év-val korábban]

Hi,

I'm trying to set a variable with the value of a method. But it doesn't work. I get this error:

java.lang.NullPointerException

#set ($assetLinkLocalService = $serviceLocator.findService("com.liferay.portlet.asset.service.AssetLinkLocalService"))
#set ($assetlinks = $assetLinkLocalService.getDirectLinks( $ae.getEntryId() ))

#set ($siz = $assetlinks.size())

But if I use this code, it print the correct value:

#set ($assetLinkLocalService = $serviceLocator.findService("com.liferay.portlet.asset.service.AssetLinkLocalService"))
#set ($assetlinks = $assetLinkLocalService.getDirectLinks( $ae.getEntryId() ))

$assetlinks.size()

Why I can't set a variable with the value?
I'm using a template web content.

Regards,
Andrés