InstanceAlreadyExistsException：jetbrains.exodus.entitystore：type = EntityStoreConfig

问题描述

什么会导致引发此异常？

Caused by: javax.management.InstanceAlreadyExistsException: jetbrains.exodus.entitystore: type=EntityStoreConfig,location=/var/xodus/master,name=persistentEntityStore
    at com.sun.jmx.mbeanserver.Repository.addMBean(Repository.java:437)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerWithRepository(DefaultMBeanServerInterceptor.java:1898)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerDynamicMBean(DefaultMBeanServerInterceptor.java:966)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerObject(DefaultMBeanServerInterceptor.java:900)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerMBean(DefaultMBeanServerInterceptor.java:324)
    at com.sun.jmx.mbeanserver.JmxMBeanServer.registerMBean(JmxMBeanServer.java:522)
    at com.sun.enterprise.v3.admin.DynamicInterceptor.registerMBean(DynamicInterceptor.java:393)
    at jetbrains.exodus.management.MBeanBase.<init>(MBeanBase.java:36)

通过此代码：

public PersistentEntityStore getPersistentEntityStore(String xodusRoot,String dir,boolean isReadOnly) {
    
        if(persistentEntityStoreCache == null) {
          persistentEntityStoreCache = buildPersistentEntityStoreCache();
        }
        PersistentEntityStore entityStore = persistentEntityStoreCache.get(xodusRoot + dir);
        if (entityStore == null) {
          Environment environment = getEnvironment(xodusRoot,dir);
          entityStore = PersistentEntityStores.newInstance(environment); // <-- here
   entityStore.getConfig().setDebugSearchForIncomingLinksOnDelete(true);
          entityStore.getConfig().setRefactoringHeavyLinks(true);
          entityStore.getConfig().setManagementEnabled(false);
          PersistentEntityStore finalEntityStore = entityStore;
          entityStore.executeInTransaction(
                  txn -> {
                    finalEntityStore.registerCustomPropertyType(
                        txn,EmbeddedEntityIterable.class,EmbeddedEntityBinding.BINDING);
                    finalEntityStore.registerCustomPropertyType(
                        txn,EmbeddedArrayIterable.class,EmbeddedEntityBinding.BINDING);
                    persistentEntityStoreCache.put(xodusRoot + dir,finalEntityStore);
                  });
        }
        PersistentEntityStore persistentEntityStore = persistentEntityStoreCache.get(xodusRoot + dir);
        return persistentEntityStore;
      }

解决方法

创建实例后，无法修改记录为Mutable at runtime: no的所有设置。至少，这样的修改没有效果。因此，您应该在创建EntityStore实例之前关闭管理，而不是在以下之后：

Environment environment = getEnvironment(xodusRoot,dir);
PersistentEntityStoreConfig config = new PersistentEntityStoreConfig().setManagementEnabled(false);
entityStore = PersistentEntityStores.newInstance(environment,config,"your EntityStore name");

java java xodus