Set uncommitted read as default in Oracle SQL Developer with DB2 database
There are a couple of ways to achieve this. Firstly, you can simply run the statement 

SET CURRENT ISOLATION UR


in your session before executing other statements.

Alternatively, you can set a property in the JDBC URL you use to connect to the database, like so:

jdbc:db2://host:port/database:defaultIsolationLevel=1;


The value 1 corresponds to the constant java.sql.Connection.TRANSACTION_READ_UNCOMMITTED (note that it is implementation-dependent and may break).