by looking the source code of MWStructArray.
public Object get(String paramString, int paramInt)
{
MWArray localMWArray = null;
try
{
localMWArray = getField(paramString, paramInt);
return localMWArray != null ? localMWArray.toArray() : null;
}
finally
{
if (localMWArray != null)
localMWArray.dispose();
}
}
It seems I should call dispose, and it is safe to do so.