From Radio 4's Woman's Hour:

To sterilize jam jars, etc:

Either place in the dish washer and leave to steam dry or wash in plenty of soapy water before rinsing in very hot water. Place in a cool oven to dry. Fill while warm with hot jam

You can place the washed and rinsed jars in a 350 degree F oven for 15 minutes to sterilize them or boil them in a large pot for 10 to 15 minutes to achieve the same results...

wouldn't putting a small amount of water in each jar and then putting them into a microvave oven on high for a few minutes,work just as well ?

Probably, Footbath, except one should sterilize the metal tops and ring sealers as well...

I wash my jars in soapy water, rinse them and put them in my electric oven for 10 minutes at about 160C (300F).

It's easy to make small quantities of jam in a microwave, when it won't need stirring and won't burn. Use the biggest bowl you can find as it will boil & bubble up when you add the sugar. A typical recipe:

1 lb soft fruit, 1 tablespoon lemon juice, 12 to 14 oz sugar.
Wash fruit, put into large mixing bowl with lemon juice. Cook on HIGH for 4 - 5 minutes or until fruit is soft. Add sugar & stir well. Cook on HIGH 11 - 12 minutes until settling point is reach. Cool slightly before putting into jars. To check setting point, put a plate in fridge to make it cold. Pour a tiny drop of mixture on plate & return to fridge. If it starts to wrinkle after 3 minutes, setting point has been reached. You will also notice a sticky build-up at the top level of liquid in the bowl.
You may need to vary cookng times according to the power of your microwave. Above times are for an elderly less powerful machine and may need to be reduced slightly.

A jam funnel (from Lakeland)is invaluable for filling the jars without making a mess. I reuse commercial jam & marmalade jars with resealable lids time & time again and just put the lids in very hot water to sterlise them.