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Messages created in the server are passed to the MessageCache
for memory management. JVM memory usage goes up as messages are added to a destination that does not have any receivers. These messages are held in the main memory until the receiver picks them up. If the MessageCache
notices that the JVM memory usage starts passing the defined limits, the MessageCache
starts moving those messages from memory to persistent storage on disk. The MessageCache
uses a least recently used (LRU) algorithm to determine which messages should go to disk.