The updates to the API should have minimal impact WRT compatibility but there are a few changes to highlight: 1. The default implementation of Statement::enquoteIdentifier is changed so that it throws SQLException if DatabaseMetaData::getIdentifierQuoteString does not return a double quote(as defined in the SQLStandard) 2. The default implementation of Statement::isSimpleIdentifier is changed to return false if the String passed to the method is a SQL standard reserved word.        The two changed methods were added in JDK 9. These changes to the       default implementation has no impact on JDBC drivers that have been       updated since JDK 9 to override these methods. 3. If there is an internal(i.e. private/protected) implementation of one of the newly added default methods, it will need to be renamed or possibly made public 4. A class cannot implement multiple interfaces that provide different default implementations of the same method. Classes that implement Array, Blob, Clob or SQLXML, plus another interface with a default implementation of close will no longer compile, and will fail at runtime with an IncompatibleClassChangeError due to conflicting default methods. Implementations of these interfaces may need to override the close method to resolve the ambiguity.