out of memory error - "PortalRuntimeException"

Hello,

We have created one web service in java and is deployed on SAP Enterprise Portal (j2EE). After deploying we got following error

"Service Unavailable 503"

"faultCode: ‑http://schemas.xmlsoap.org/soap/envelope/}Server

faultSubcode:

faultString: PortalRuntimeException

faultActor: [TVSAPPDD1] java.lang.String

faultNode:

faultDetail:

error_OutOfMemoryError type>com.sapportals.portal.prt.runtime.PortalRuntimeException</type>

PortalRuntimeException"

is there any specific reason behind this??

Any Help??

Thanks,

Prashant