Simple to reproduce:

DatabaseMetaData dbMeta = con.getMetaData();

System.out.println("dbMeta.storesMixedCaseQuotedIdentifiers() = " + dbMeta.storesMixedCaseQuotedIdentifiers());
System.out.println("dbMeta.storesUpperCaseQuotedIdentifiers() = " + dbMeta.storesUpperCaseQuotedIdentifiers());
System.out.println("dbMeta.storesLowerCaseQuotedIdentifiers() = " + dbMeta.storesLowerCaseQuotedIdentifiers());

But depending on the JDBC driver used, the results are different:

Talking to MariaDB with a MySQL 5.1.18 JDBC Driver:
dbMeta.storesMixedCaseQuotedIdentifiers() = true
dbMeta.storesUpperCaseQuotedIdentifiers() = true
dbMeta.storesLowerCaseQuotedIdentifiers() = false

Talking to MariaDB with the MariaDB 1.1.3 JDBC Driver:
dbMeta.storesMixedCaseQuotedIdentifiers() = false
dbMeta.storesUpperCaseQuotedIdentifiers() = true
dbMeta.storesLowerCaseQuotedIdentifiers() = false

Talking to MySQL with the MySQL JDBC Driver:
dbMeta.storesMixedCaseQuotedIdentifiers() = false
dbMeta.storesUpperCaseQuotedIdentifiers() = true
dbMeta.storesLowerCaseQuotedIdentifiers() = true

Talking to MySQL with the MariaDB JDBC Driver:
dbMeta.storesMixedCaseQuotedIdentifiers() = false
dbMeta.storesUpperCaseQuotedIdentifiers() = true
dbMeta.storesLowerCaseQuotedIdentifiers() = false

I would have expected the return results to be the same regardless which JDBC driver implementation was used.