Displaying Debug Messages to the Console
Even before starting to use the actual debugger, running with the framework’s diagnostic logging turned on can be helpful to see what is happening when the problem occurs. To turn on diagnostic logging, set the Java system property named jbo.debugoutput to the value console. Legal values for this flag are silent, console, file, and ADFLogger—this last value is discussed shortly.
To set this system property while running your application inside JDeveloper, edit project properties and select the Run/Debug/Profile node in the tree at the left. You can either edit an existing run configuration, such as Default, or create a new one. Then add the following string to the Java Options field: -Djbo.debugoutput=console