There's nothing I can found this question .
Does the JVM code cache area exist in heap or metaspace in jdk 8?
Neither in Heap nor in Metaspace. In HotSpot JVM Code Cache is a separate off-heap area. Its size is controlled by -XX:ReservedCodeCacheSize
option.
On the "Memory" tab of Java Mission Control you'll find the Code Cache among other JVM memory pools: