Welcome to... "Micro-Lesson 266"
This melody line works well over a traditional set of jazz chord changes following the popular jazz-harmony pattern of, "I, VI, IV, II, V."
Starting from the outline of the key's tonic chord of, "Bbmaj7" the melody flows through the tones of mostly the, "B Major Pentatonic," after the chord arpeggio. The second measure introduces sounds of the, "VI-chord," of, "Gm7." All eighth-notes within this melody are swung and there are also plenty of triplet phrases. This is especially evident in the third measure where we cover sounds of our IV-chord of, "Ebmaj7."
The initial eighth-notes are swung, but after that three eighth-note triplets are steady throughout the remainder of the bar. The end of this melody line introduces the final "II-V7" resolution with the chords of, "Cm7 and F7."
One other interesting idea that occurs across this melody is the application of both major and minor 3rd's and 7th's from each of the chords in each measure. These tones end up being the core device for creating the, "Jazzy," effect within the short phrase.
Keep this in mind when you're creating your own jazzy lines. Learn the phrases, build them up with a metronome and then play them with these changes in the background. Record them, or have a friend play them with you. However you do it, be sure to practice this melody, "with the backing chords." Have fun and Enjoy!
Micro Lesson 266: "Bb Major" Jazz-Swing Melody