我可以设置从jar文件运行的Java最大堆大小吗？

I am launching a java jar file which often requires more than the default 64MB max heap size. A 256MB heap size is sufficient for this app though. Is there anyway to specify (in the manifest maybe?) to always use a 256MB max heap size when launching the jar? (More specific details below, if needed.)I am launching a java jar file which often requ