# UnexpectedLiquibaseException: java.lang.ClassCastException

**URL:** <https://forum.liquibase.org/t/unexpectedliquibaseexception-java-lang-classcastexception/5292>\
**Category:** General Discussion\
**Created:** [April 6, 2021, 8:05am UTC](https://forum.liquibase.org/t/unexpectedliquibaseexception-java-lang-classcastexception/5292 "2021-04-06T08:05:32Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Gotham333](https://avatars.discourse-cdn.com/v4/letter/g/c2a13f/32.png) [@Gotham333](https://forum.liquibase.org/u/Gotham333)\
**Post date:** [April 6, 2021, 8:05am UTC](https://forum.liquibase.org/t/unexpectedliquibaseexception-java-lang-classcastexception/5292/1 "2021-04-06T08:05:32Z")

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Hi,  
We are getting the below error when trying to connect to cassandra database using liquibase version, 3.10.3 and liquibase cassandra ext, 4.3.1.

Caused by: liquibase.exception.UnexpectedLiquibaseException: java.lang.ClassCastException: liquibase.executor.ExecutorService cannot be cast to liquibase.SingletonObject  
at liquibase.Scope.getSingleton(Scope.java:200) ~[liquibase-core-3.10.3.jar:na]  
at liquibase.ext.cassandra.lockservice.LockServiceCassandra.acquireLock(LockServiceCassandra.java:52) ~[liquibase-cassandra-4.0.0.jar:na]  
at liquibase.lockservice.StandardLockService.waitForLock(StandardLockService.java:213) ~[liquibase-core-3.10.3.jar:na]  
at liquibase.Liquibase.update(Liquibase.java:183) ~[liquibase-core-3.10.3.jar:na]  
at liquibase.Liquibase.update(Liquibase.java:178) ~[liquibase-core-3.10.3.jar:na]  
at liquibase.Liquibase.update(Liquibase.java:174) ~[liquibase-core-3.10.3.jar:na]

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<div class="post-metadata">

**Author:** ![ronak](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.liquibase.org/ronak/32/221_2.png) [@ronak](https://forum.liquibase.org/u/ronak)\
**Post date:** [April 20, 2021, 2:44am UTC](https://forum.liquibase.org/t/unexpectedliquibaseexception-java-lang-classcastexception/5292/2 "2021-04-20T02:44:30Z")

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Hi @Gotham333 ,

Could we see the complete stacktrace? Also have you tried using the same version of extension as your core liquibase version (3.10.3), does the error happen then also?