what does mean cassandra warnings: Unable to lock JVM memory and MemoryMeter uninitialized
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I'm getting the following warnings on cassandra - what does it mean? and Is it an issue?
And how can I solve this?

    WARN 15:32:06,772 Unable to lock JVM memory (ENOMEM). This can result in part of the JVM being swapped out, especially with mmapped I/O enabled. Increase RLIMIT_MEMLOCK or run Cassandra as root.

    WARN 15:33:20,860 MemoryMeter uninitialized (jamm not specified as java agent); assuming liveRatio of 10.0.  Usually this means cassandra-env.sh disabled jamm because you are using a buggy JRE; upgrade to the Sun JRE instead