此问题已被官方采纳，在JDK24+b27中修复：https://bugs.openjdk.org/browse/JDK-8343377
本项目用于对比Java17和Java21下反射调用clone函数时性能差异
This project used for compare the performance difference when reflection invoke clone method in Java 17 and Java 21.
环境依赖：
dependent:
1.oracle jdk 17
2.oracle jdk 21
运行方式：
Test Way:
将gradle工程导入到ide环境中，执行任务 gradle jmh
Import gradle project into ide,run gradle jmh
注意：需要添加jvm参数--add-opens java.base/java.lang=ALL-UNNAMED，才能正确运行反射代码
note:Need jvm args --add-opens java.base/java.lang=ALL-UNNAMED to run correctly.
case说明：
case describe:
case1：通过Object类的Clone方法直接反射无本地Clone方法的数据类Data
case1: By Reflecting Object.class's clone method to invoke com.monk.Data.class(no have clone method implement)
case2：通过Object类的Clone方法直接反射有本地Clone方法的数据类DataWithOverride
case2: By Reflecting Object.class's clone method to invoke com.monk.DataWithOverride.class(have clone method implement)
case3：通过DataWithClone类的Clone方法自身本地的Clone方法的数据类DataWithOverride
case3:By Reflecting com.monk.DataWithOverride.class's clone method to invoke com.monk.DataWithOverride.class(have clone method implement)
HashCode测试用例和toString测试用例同上
HashCode case and toString are same like clone case.
参考结果(I7 14700K)：
Reference result(I7 14700K):
JDK17:
Benchmark Mode Cnt Score Error Units
RunBenchmark.cloneCase1 thrpt 5 830871722.632 ± 14902415.558 ops/s
RunBenchmark.cloneCase2 thrpt 5 832256881.789 ± 9305066.153 ops/s
RunBenchmark.cloneCase3 thrpt 5 827842981.397 ± 8629836.251 ops/s
RunBenchmark.hashCodeCase1 thrpt 5 726644716.300 ± 4504879.585 ops/s
RunBenchmark.hashCodeCase2 thrpt 5 726540126.956 ± 7249056.369 ops/s
RunBenchmark.hashCodeCase3 thrpt 5 729054390.940 ± 11904383.303 ops/s
RunBenchmark.toStringCase1 thrpt 5 42906690.075 ± 268508.159 ops/s
RunBenchmark.toStringCase2 thrpt 5 41641490.800 ± 271577.545 ops/s
RunBenchmark.toStringCase3 thrpt 5 41824727.616 ± 440507.690 ops/s
JDK21;
Benchmark Mode Cnt Score Error Units
RunBenchmark.cloneCase1 thrpt 5 8783640.822 ± 46196.518 ops/s
RunBenchmark.cloneCase2 thrpt 5 13045394.145 ± 157121.364 ops/s
RunBenchmark.cloneCase3 thrpt 5 2320020521.800 ± 56423864.542 ops/s
RunBenchmark.hashCodeCase1 thrpt 5 11495229.964 ± 110515.482 ops/s
RunBenchmark.hashCodeCase2 thrpt 5 11488996.620 ± 72449.931 ops/s
RunBenchmark.hashCodeCase3 thrpt 5 1590063332.584 ± 15874384.555 ops/s
RunBenchmark.toStringCase1 thrpt 5 40532553.791 ± 349765.261 ops/s
RunBenchmark.toStringCase2 thrpt 5 40912699.225 ± 339420.788 ops/s
RunBenchmark.toStringCase3 thrpt 5 40991023.028 ± 280145.682 ops/s~~~~
测试显示同样的代码，在不同的测试用例下，JDK21比JDK17的反射Clone,HashCode等native方法时性能出现显著下降，toString等非native方法则变化不明显