[question] Is ehcache virtual thread / loom friendly?

[wyhasany]

I wonder if ehcache is loom-friendly - e.g. does not pin the platform threads?

[JT-Alchemy]

Would also like to know this. Also any suggested patterns for leveraging virtual threads with EH Cache if it's not directly supportive of them yet 🙏

[VIJAY-SUBRAMANIAM]

It seems no, that ConcurrentHashMap is blocking the carrier thread. ehcache uses a ConcurrentHashMap that is built on synchronized blocks, such as computeIfAbsent.

This was the issue noticed when switched spring framework to use virtual threads

"org.springframework.amqp.rabbit.RabbitListenerEndpointContainer#0-1" #34 [41] prio=5 os_prio=0 cpu=83638.00ms elapsed=21635.21s tid=0x00007fb31f83b1e0 nid=41 waiting for monitor entry [0x00007fb3208ff000]
java.lang.Thread.State: BLOCKED (on object monitor)
at org.ehcache.impl.internal.concurrent.ConcurrentHashMap.computeIfPresent(ConcurrentHashMap.java:1840)
- waiting to lock <0x00000000c8a79370> (a org.ehcache.impl.internal.concurrent.ConcurrentHashMap$Node)
at org.ehcache.impl.internal.store.heap.SimpleBackend.computeIfPresent(SimpleBackend.java:121)
at org.ehcache.impl.internal.store.heap.OnHeapStore.evict(OnHeapStore.java:1591)
at org.ehcache.impl.internal.store.heap.OnHeapStore.enforceCapacity(OnHeapStore.java:1558)
at org.ehcache.impl.internal.store.heap.OnHeapStore.resolveFault(OnHeapStore.java:785)
at org.ehcache.impl.internal.store.heap.OnHeapStore.getOrComputeIfAbsent(OnHeapStore.java:705)
at org.ehcache.impl.internal.store.tiering.TieredStore.get(TieredStore.java:88)
at org.ehcache.core.Ehcache.doGet(Ehcache.java:89)
at org.ehcache.core.EhcacheBase.get(EhcacheBase.java:125)
at org.ehcache.jsr107.Eh107Cache.get(Eh107Cache.java:90)
at org.springframework.cache.jcache.JCacheCache.lookup(JCacheCache.java:84)
at org.springframework.cache.support.AbstractValueAdaptingCache.get(AbstractValueAdaptingCache.java:58)
at org.springframework.cache.interceptor.AbstractCacheInvoker.doGet(AbstractCacheInvoker.java:78)
at org.springframework.cache.interceptor.CacheAspectSupport.findInCaches(CacheAspectSupport.java:538)
at org.springframework.cache.interceptor.CacheAspectSupport.findCachedValue(CacheAspectSupport.java:495)
at org.springframework.cache.interceptor.CacheAspectSupport.execute(CacheAspectSupport.java:445)
at org.springframework.cache.interceptor.CacheAspectSupport.execute(CacheAspectSupport.java:409)
at org.springframework.cache.interceptor.CacheInterceptor.invoke(CacheInterceptor.java:65)