Unlike traditional stepping, which works at the statement level of the language, step-by-step mode works at a much higher level and stops on entry to every object loaded by the JVM or server. You use step-by-step mode to get to the object you want to debug and then use traditional stepping (step into, step over and step return) to control debugging at the statement level.
To determine which languages support step-by-step debugging, open the Java and mixed language debug preference page. In this page, supported languages are listed for step-by-step debugging enablement. For information about setting Java and mixed language debugging preferences, see the related topic.