These were the eggs of the Leopard Butterfly on the leaves of the Weeping Willow (scientific name: Salix babylonica).
It was hard for me to capture the numerous butterflies flying against the wind to lay their eggs on the flapping leaves of the Willow tree. I counted at least 5 females flying around and ovipositing their eggs on these leaves.
Interestingly, there was not a single caterpillar in sight.