Migrating the code might not be needed, or it might only need small adjustments, because DB2 V10.5 emulates much (but not all) Oracle functionality, from DDL to PL/SQL. Study the DB2 docs about this. You don't need to rewrite in many simple cases - just use DB2 Oracle-emulation.
Migrating the data can be done either by exporting from Oracle to either flat-files (delimited or fixed-width-positional) and then loading these into the pre-created DB2 database whose Oracle-DDL has already been created/adjusted for DB2, or alternatively you can copy the data from Oracle into DB2 via DB2 federation capabilities (if your DB2 licence and DB2 server platform allow this of course). With export/load you need to pay particular attention to code page issues to ensure no data loss or conversion errors.
Your project should involve people with direct practical experience with this migration, and pay a large amount of attention to the planning, the implications on the DB2 design of any existing/new SLAs like RTO/RPO, and other required connectivity and special security requirements that might exist.
If you try it without using experienced people don't be surprised if the project fails or significantly exceeds budget or performs badly.
There is a free data movement tool form IBM which you can use to migrate from oracle to DB2 LUW. Check the link below for details. I have used it to migrate data from AS/400 to DB2 LUW with minor issues. The tool does not require federation license as it uses jdbc for data transfer.
It also migrates views, triggers, etc.