Mysql error: Unknown character set: & #39; utf8mb4 & #39;, mysqlutf8mb4

Mysql error: Unknown character set: 'utf8mb4', mysqlutf8mb4
Com. mysql. jdbc. exceptions. jdbc4.MySQLSyntaxErrorException: Unknown character set: 'utf8mb4'
At sun. reflect. NativeConstructorAccessorImpl. newInstance0 (Native Method)
At sun. reflect. nativeconstruct%cessorimpl. newInstance (nativeconstruct%cessorimpl. java: 57)
At sun. reflect. delegatingconstruct%cessorimpl. newInstance (delegatingconstruct%cessorimpl. java: 45)
At java. lang. reflect. Constructor. newInstance (Constructor. java: 526)
At com. mysql. jdbc. Util. handleNewInstance (Util. java: 411)
At com. mysql. jdbc. Util. getInstance (Util. java: 386)
At com. mysql. jdbc. SQLError. createSQLException (SQLError. java: 1052)
At com. mysql. jdbc. MysqlIO. checkErrorPacket (MysqlIO. java: 3609)
At com. mysql. jdbc. MysqlIO. checkErrorPacket (MysqlIO. java: 3541)
At com. mysql. jdbc. MysqlIO. sendCommand (MysqlIO. java: 2002)
At com. mysql. jdbc. MysqlIO. sqlQueryDirect (MysqlIO. java: 2163)
At com.mysql.jdbc.ConnectionImpl.exe cSQL (ConnectionImpl. java: 2618)
At com. mysql. jdbc. ConnectionImpl. configureClientCharacterSet (ConnectionImpl. java: 1880)
At com. mysql. jdbc. ConnectionImpl. initializePropsFromServer (ConnectionImpl. java: 3499)
At com. mysql. jdbc. ConnectionImpl. connectOneTryOnly (ConnectionImpl. java: 2384)
At com. mysql. jdbc. ConnectionImpl. createNewIO (ConnectionImpl. java: 2153)
At com. mysql. jdbc. ConnectionImpl. <init> (ConnectionImpl. java: 792)
At com. mysql. jdbc. JDBC4Connection. <init> (JDBC4Connection. java: 47)
At sun. reflect. NativeConstructorAccessorImpl. newInstance0 (Native Method)
At sun. reflect. nativeconstruct%cessorimpl. newInstance (nativeconstruct%cessorimpl. java: 57)
At sun. reflect. delegatingconstruct%cessorimpl. newInstance (delegatingconstruct%cessorimpl. java: 45)
At java. lang. reflect. Constructor. newInstance (Constructor. java: 526)
At com. mysql. jdbc. Util. handleNewInstance (Util. java: 411)
At com. mysql. jdbc. ConnectionImpl. getInstance (ConnectionImpl. java: 381)
At com. mysql. jdbc. NonRegisteringDriver. connect (NonRegisteringDriver. java: 305)
At java. SQL. DriverManager. getConnection (DriverManager. java: 571)
At java. SQL. DriverManager. getConnection (DriverManager. java: 215)
At com. silence. mysqlTest2.JDBCTools. getConnection (JDBCTools. java: 130)
At com. silence. mysqlTest2.JDBCTest. testInsertBlob (JDBCTest. java: 82)
At sun. reflect. NativeMethodAccessorImpl. invoke0 (Native Method)
At sun. reflect. NativeMethodAccessorImpl. invoke (NativeMethodAccessorImpl. java: 57)
At sun. reflect. DelegatingMethodAccessorImpl. invoke (DelegatingMethodAccessorImpl. java: 43)
At java. lang. reflect. Method. invoke (Method. java: 606)
At org. junit. runners. model. FrameworkMethod $1. runReflectiveCall (FrameworkMethod. java: 47)
At org. junit. internal. runners. model. ReflectiveCallable. run (ReflectiveCallable. java: 12)
At org. junit. runners. model. FrameworkMethod. invokeExplosively (FrameworkMethod. java: 44)
At org. junit. internal. runners. statements. InvokeMethod. evaluate (InvokeMethod. java: 17)
At org. junit. runners. ParentRunner. runLeaf (ParentRunner. java: 271)
At org. junit. runners. BlockJUnit4ClassRunner. runChild (BlockJUnit4ClassRunner. java: 70)
At org. junit. runners. BlockJUnit4ClassRunner. runChild (BlockJUnit4ClassRunner. java: 50)
At org. junit. runners. ParentRunner $ 3.run( ParentRunner. java: 238)
At org. junit. runners. ParentRunner $1. schedule (ParentRunner. java: 63)
At org. junit. runners. ParentRunner. runChildren (ParentRunner. java: 236)
At org. junit. runners. ParentRunner. access $000 (ParentRunner. java: 53)
At org. junit. runners. ParentRunner $2. evaluate (ParentRunner. java: 229)
At org. junit. runners. ParentRunner. run (ParentRunner. java: 309)
At org. eclipse. jdt. internal. junit4.runner. JUnit4TestReference. run (JUnit4TestReference. java: 50)
At org. eclipse. jdt. internal. junit. runner. TestExecution. run (TestExecution. java: 38)
At org. eclipse. jdt. internal. junit. runner. RemoteTestRunner. runTests (RemoteTestRunner. java: 467)
At org. eclipse. jdt. internal. junit. runner. RemoteTestRunner. runTests (RemoteTestRunner. java: 683)
At org. eclipse. jdt. internal. junit. runner. RemoteTestRunner. run (RemoteTestRunner. java: 390)
At org. eclipse. jdt. internal. junit. runner. RemoteTestRunner. main (RemoteTestRunner. java: 197)

Unknown character set: 'utf8mb4'. At the beginning, I thought it was caused by the inconsistent character encoding of mysql and the project encoding.

I spent most of my time searching for a long time on the Internet. In fact, it's not a problem with character encoding, it's a problem with the mysql driver-

Connector-java5.1.26 changed to mysql-connector-java5.1.6 and there is no error.