The following error indicates that you might be trying to connect to a HiveServer2 which is running in secure mode (means Kerberized). So please check your Hive config to know "hive.server2.autnentication" if it is set to "kerberos"
jdbc:hive2://xxxxxxxxxxx:10000/default: Peer indicated failure: Unsupported mechanism type PLAIN (state=08S01,code=0)
If that is the case then you should be adding the principal in the URL as following"
# kinit -kt /etc/security/keytabs/hive.service.keytab hive/tesths2.example.com@EXAMPLE.COM
beeline> !connect jdbc:hive2://HS2_hostname:10000/default;principal=hive/HS2_HOST@REALM
Here you will need to replace the "principal=hive/HS2_HOST@REALM" with your HS2 principal and you might be having your own keytab. So you will need to choose it accordingly.
There are some examples for Secure and Non Secure Hive Server 2 connection URLs: https://community.hortonworks.com/articles/4103/hiveserver2-jdbc-connection-url-examples.html