The invention relates to memory overload management for Java virtual machines (JVMs) in Web application sever systems. Disclosed is a method and system of memory overload management for a Web application sever system, wherein the Web application sever system comprises multiple JVMs, the method comprising: determining one or more replica shards for which replacement shall be performed; determining one or more target JVMs for storing a corresponding replica shard set including at least one replica shard from the one or more replica shards; and for each target JVM, performing the following: judging whether the free memory of the target JVM is adequate for storing the corresponding replica shard set; if the judging result is negative, performing the following: causing the target JVM to suspend the creation of session until the free memory of the target JVM becomes adequate for storing the corresponding replica shard set.