Green-Flame Blade reads:

As part of the action used to cast this spell, you must make a melee attack with a weapon against one creature within the spell’s range, otherwise the spell fails. On a hit, the target suffers the attack’s normal effects, and green fire leaps from the target to a different creature of your choice that you can see within 5 feet of it. The second creature takes fire damage equal to your spellcasting modifier.

Since the caster fits the bolded criteria, does this mean he must target himself if no other creatures are available?

The description of the green-flame blade cantrip (SCAG, p. 143) reads:

As part of the action used to cast this spell, you must make a melee attack with a weapon against one creature within the spell’s range, otherwise the spell fails. On a hit, the target suffers the attack’s normal effects, and green fire leaps from the target to a different creature of your choice that you can see within 5 feet of it. The second creature takes fire damage equal to your spellcasting modifier.

Since the caster fits the bolded criteria, does this mean he must target himself if no other creatures are available?