Unable to register MBean [SftpPool

org.springframework.jmx.export.UnableToRegisterMBeanException: Unable to register MBean [SftpPool [maxTotal=8, blockWhenExhausted=true, maxWaitMillis=-1, lifo=true, fairness=false, testOnCreate=false, testOnBorrow=false, testOnReturn=false, testWhileIdle=false, timeBetweenEvictionRunsMillis=-1, numTestsPerEvictionRun=3, minEvictableIdleTimeMillis=1800000, softMinEvictableIdleTimeMillis=-1, evictionPolicy=org.apache.commons.pool2.impl.DefaultEvictionPolicy@131c0b6f, closeLock=java.lang.Object@7f030c72, closed=false, evictionLock=java.lang.Object@68d8ae27, evictor=null, evictionIterator=null, factoryClassLoader=java.lang.ref.WeakReference@18513c23, oname=org.apache.commons.pool2:type=GenericObjectPool,name=pool, creationStackTrace=java.lang.Exceptionat org.apache.commons.pool2.impl.BaseGenericObjectPool.<init>(BaseGenericObjectPool.java:147)at org.apache.commons.pool2.impl.GenericObjectPool.<init>(GenericObjectPool.java:110)at com.vipsoft.his.hospital.util.SftpPool.<init>(SftpPool.java:9)at com.vipsoft.his.hospital.config.SftpConfig.sftpPool(SftpConfig.java:22)