Remove use of String.intern()

patch by Benjamin Lerer; reviewed by Brandon Williams for CASSANDRA-15810

CHANGES.txt

@@ -1,4 +1,5 @@
 4.0-beta4
+ * Remove use of String.intern() (CASSANDRA-15810)
  * Fix the missing bb position in ByteBufferAccessor.getUnsignedShort (CASSANDRA-16249)
  * Make sure OOM errors are rethrown on truncation failure (CASSANDRA-16254)
  * Send back client warnings when creating too many tables/keyspaces (CASSANDRA-16309)

conf/jvm-server.options

@@ -103,9 +103,6 @@
 # Per-thread stack size.
 -Xss256k
 
-# Larger interned string table, for gossip's benefit (CASSANDRA-6410)
--XX:StringTableSize=1000003
-
 # Make sure all memory is faulted and zeroed on startup.
 # This helps prevent soft faults in containers and makes
 # transparent hugepage allocation more effective.

src/java/org/apache/cassandra/gms/VersionedValue.java

@@ -87,11 +87,7 @@ public class VersionedValue implements Comparable<VersionedValue>
     private VersionedValue(String value, int version)
     {
         assert value != null;
-        // blindly interning everything is somewhat suboptimal -- lots of VersionedValues are unique --
-        // but harmless, and interning the non-unique ones saves significant memory.  (Unfortunately,
-        // we don't really have enough information here in VersionedValue to tell the probably-unique
-        // values apart.)  See CASSANDRA-6410.
-        this.value = value.intern();
+        this.value = value;
         this.version = version;
     }