Its more important to know how Oracle works than to know SQL syntax.
Especially when it comes to indexes, PreparedStatements .vs. Statements etc.
Following up Trever's post I would say using Stored Proceedures just makes an application harder to maintain (version control etc).
Data mapping is best handled by powercenter or somthing rather than writing your own code.
As to OCP's who are programmers, well I hope to be one soon
Generally speaking 'A little knowledge is very dangerous' applies to databases. But the reverse is true too, if you know about Oracle's library cache, row cache, execution plans, function based indexes, index hints...etc etc etc it will make you a great programmer.
As with any topic it takes time to learn and there is a lot of information to soak up. I have about a dozen Oracle books and they are VERY dry to read. However, as you have probably realised the Java+Oracle skillset commands a better salary than Java alone.
check out my site for OCP notes.