From a5a349f289dd9b579c3026224186b6ea82dbd9b5 Mon Sep 17 00:00:00 2001
From: Yutong Xiao <yutongsean@gmail.com>
Date: Wed, 27 Oct 2021 22:02:59 +0800
Subject: [PATCH] HBASE-26392 Update ClassSize.BYTE_BUFFER for JDK17 (#3784)

Signed-off-by: Duo Zhang <zhangduo@apache.org>
---
 .../apache/hadoop/hbase/util/ClassSize.java   |  6 +++++-
 .../org/apache/hadoop/hbase/util/JVM.java     | 19 +++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/hbase-common/src/main/java/org/apache/hadoop/hbase/util/ClassSize.java b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/ClassSize.java
index b983fc0f3db..4e6005637bf 100644
--- a/hbase-common/src/main/java/org/apache/hadoop/hbase/util/ClassSize.java
+++ b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/ClassSize.java
@@ -257,7 +257,11 @@ public class ClassSize {
     LINKEDLIST_ENTRY = align(OBJECT + (2 * REFERENCE));
 
     //noinspection PointlessArithmeticExpression
-    BYTE_BUFFER = align(OBJECT + REFERENCE +
+    BYTE_BUFFER = JVM.getJVMSpecVersion() < 17 ?
+      align(OBJECT + REFERENCE +
+        (5 * Bytes.SIZEOF_INT) +
+        (3 * Bytes.SIZEOF_BOOLEAN) + Bytes.SIZEOF_LONG) + align(ARRAY) :
+      align(OBJECT + 2 * REFERENCE +
         (5 * Bytes.SIZEOF_INT) +
         (3 * Bytes.SIZEOF_BOOLEAN) + Bytes.SIZEOF_LONG) + align(ARRAY);
 
diff --git a/hbase-common/src/main/java/org/apache/hadoop/hbase/util/JVM.java b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/JVM.java
index 6657481ed02..8bd70e486fb 100644
--- a/hbase-common/src/main/java/org/apache/hadoop/hbase/util/JVM.java
+++ b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/JVM.java
@@ -60,6 +60,21 @@ public class JVM {
 
   private static final String JVMVersion = System.getProperty("java.version");
 
+  /**
+   * The raw String of java specification version.
+   * "1.8" for java8, "9","10"... for Java 9, 10...
+   */
+  private static final String JVM_SPEC_VERSION_STRING =
+    System.getProperty("java.specification.version");
+
+  /**
+   * The Integer represent of JVM_SPEC_VERSION, for the JVM version comparison.
+   * Java 8, 9, 10 ... will be noted as 8, 9 10 ...
+   */
+  private static final int JVM_SPEC_VERSION = JVM_SPEC_VERSION_STRING.contains(".") ?
+    (int) (Float.parseFloat(JVM_SPEC_VERSION_STRING) * 10 % 10) :
+    Integer.parseInt(JVM_SPEC_VERSION_STRING);
+
   /**
    * Constructor. Get the running Operating System instance
    */
@@ -106,6 +121,10 @@ public class JVM {
     return ibmvendor && JVMVersion.contains("1.6.0");
   }
 
+  public static int getJVMSpecVersion() {
+    return JVM_SPEC_VERSION;
+  }
+
   /**
    * Load the implementation of UnixOperatingSystemMXBean for Oracle jvm
    * and runs the desired method.