diff --git a/CHANGES.txt b/CHANGES.txt
index 6b81061a5d..bdda12f603 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,6 +1,7 @@
 5.1
  * Clean up obsolete functions and simplify cql_version handling in cqlsh (CASSANDRA-18787)
 Merged from 5.0:
+ * Fix accessing java.nio.Bits.TOTAL_CAPACITY in Java17 (CASSANDRA-18848)
  * Remove metrics-reporter-config dependency (CASSANDRA-18743)
  * Fix SAI's SegmentMetadata min and max primary keys (CASSANDRA-18734)
  * Remove commons-codec dependency (CASSANDRA-18772)
diff --git a/build.xml b/build.xml
index cad293c716..0eef07847c 100644
--- a/build.xml
+++ b/build.xml
@@ -262,6 +262,7 @@
         <string>--add-opens jdk.compiler/com.sun.tools.javac=ALL-UNNAMED</string>
         <string>--add-opens java.base/java.lang=ALL-UNNAMED</string>
         <string>--add-opens java.base/java.util=ALL-UNNAMED</string>
+        <string>--add-opens java.base/java.nio=ALL-UNNAMED</string>
 
         <string>--add-opens java.rmi/sun.rmi.transport.tcp=ALL-UNNAMED</string>
     </resources>
diff --git a/conf/jvm17-clients.options b/conf/jvm17-clients.options
index 4c12fa378c..57b009f582 100644
--- a/conf/jvm17-clients.options
+++ b/conf/jvm17-clients.options
@@ -52,6 +52,7 @@
 --add-opens jdk.compiler/com.sun.tools.javac=ALL-UNNAMED
 --add-opens java.base/java.lang.reflect=ALL-UNNAMED
 --add-opens java.base/java.util=ALL-UNNAMED
+--add-opens java.base/java.nio=ALL-UNNAMED
 
 
 # The newline in the end of file is intentional
diff --git a/conf/jvm17-server.options b/conf/jvm17-server.options
index 39c1810d16..fb5d4517a6 100644
--- a/conf/jvm17-server.options
+++ b/conf/jvm17-server.options
@@ -86,6 +86,7 @@
 --add-opens jdk.compiler/com.sun.tools.javac=ALL-UNNAMED
 --add-opens java.base/java.lang=ALL-UNNAMED
 --add-opens java.base/java.util=ALL-UNNAMED
+--add-opens java.base/java.nio=ALL-UNNAMED
 
 ### GC logging options -- uncomment to enable
 
diff --git a/src/java/org/apache/cassandra/service/GCInspector.java b/src/java/org/apache/cassandra/service/GCInspector.java
index 8f922156ca..16b6665c69 100644
--- a/src/java/org/apache/cassandra/service/GCInspector.java
+++ b/src/java/org/apache/cassandra/service/GCInspector.java
@@ -67,16 +67,7 @@ public class GCInspector implements NotificationListener, GCInspectorMXBean
         try
         {
             Class<?> bitsClass = Class.forName("java.nio.Bits");
-            Field f;
-            try
-            {
-                f = bitsClass.getDeclaredField("totalCapacity");
-            }
-            catch (NoSuchFieldException ex)
-            {
-                // in Java11 it changed name to "TOTAL_CAPACITY"
-                f = bitsClass.getDeclaredField("TOTAL_CAPACITY");
-            }
+            Field f = bitsClass.getDeclaredField("TOTAL_CAPACITY");
             f.setAccessible(true);
             temp = f;
         }