Problem with Liquibase (using Java 8) to connect DB2

I am using liquibase 3.3.2. My class extends DB2Database and it overrides isReservedWord method. When I use Java 7 it works fine and it always uses my own  isReservedWord class. But when I use Java 8, liquibase ignores my extended class and uses isReservedWord in AbstractJdbcDatabase. Could please let me know why it behaves likes this with Java 8?

Thanks,

Nick