Minecraft 1.15 is a major update of the Java edition, adding new a mob like bees and new items like honeycomb and so on. We will be covering a few things coming to the game. For techincal stuff like commands and what not, you can read more about that here on Gamepedia's Minecraft wiki.
Bees are a new flying mob being added into Minecraft. Bees, of course, will collect honey and if you're not nice to them they will sting. Mobs are a neutral by default, and will become hostile if you hit them just like wolfs. Adult bees are half a block wide and half a block tall, while the baby bees are a quarter block wide and a quarter block tall. Mojang made bees these sizes, as they find it to be the cutest size for the game, after all this game is aimed for kids(adults can play too btw). Bees are the first flying insects and first flying neutral mobs introduced to Minecraft. The other insects are silverfish and endermites. Bees are the only arthropod mob that do not count as mobs necessary to earning the Monster Hunter / Monsters Hunted advancements.
Bees can be found flying around in groups around bee hives that are hanging from oak to birch trees. There is a 5% of finding a bee hive in these trees during world generation. Hives can be commonly found in the Flower Forest biome, for obvious reasons.
To breed bees, you are to use a flower, then they the two bees will breed and create a baby bee granting the player experience. After a pair of bees get done breeding, they have to wait 5 minutes to breed again.
Bee nest is a new block added to game with the addition of bees. Obviously they're used to store honey and is a home for bees. As for bee hives, they're a crafted version of a bee nest and probably should be used to create bee farms. With hives, you can start collecting honey. They are several ways to obtain the honey from these hives, you can use a shear to get honeycombs, or use an empty glass bottle to get a glass of honey.
Another addition of bees is the new honey block! These blocks can be more stickier than slime blocks, jumping will be very small, makes you walk very slow, can not be sprint on, and will move any mobs on it when pushed by a piston.
New gamerules were added:
fireDamage: Weather a player should take fire damage
fallDamage: Weather a player should take fall damage
doImmediateRespawn: Players respawn immediately without showing the death screen
doInsomnia: Weather phantoms are to spawn during the nighttime
Learn More about Minecraft 1.15
If you want more details about the update like new commands and other stuff, you can get a lot of information from Gamepedia's Minecraft Wiki. Click here to go there now.