XWiki 1.0b4 doesn't compile with Sun's JDK 1.6

When I try to compile XWiki 1.0b4 source code I get the following errors concerning com.xpn.xwiki.store.XWikiJDBCConnection.java :

The type XWikiJDBCConnection must implement the inherited abstract method Connection.createArrayOf(String, Object[])
The type XWikiJDBCConnection must implement the inherited abstract method Connection.createBlob()
The type XWikiJDBCConnection must implement the inherited abstract method Connection.createClob()
The type XWikiJDBCConnection must implement the inherited abstract method Connection.createNClob()
The type XWikiJDBCConnection must implement the inherited abstract method Connection.createSQLXML()
The type XWikiJDBCConnection must implement the inherited abstract method Connection.createStruct(String, Object[])
The type XWikiJDBCConnection must implement the inherited abstract method Connection.getClientInfo()
The type XWikiJDBCConnection must implement the inherited abstract method Connection.getClientInfo(String)
The type XWikiJDBCConnection must implement the inherited abstract method Connection.isValid(int)
The type XWikiJDBCConnection must implement the inherited abstract method Connection.setClientInfo(Properties)
The type XWikiJDBCConnection must implement the inherited abstract method Connection.setClientInfo(String, String)
The type XWikiJDBCConnection must implement the inherited abstract method Wrapper.isWrapperFor(Class<?>)
The type XWikiJDBCConnection must implement the inherited abstract method Wrapper.unwrap(Class<T>)

Regards