I planted tomato seeds in April. I have 5 healthy plants, with no fruit. What is wrong. This happened to me last year also.

How much sun do the plants get? How did you prepare your bed? Do they otherwise appear healthy? What variety?

Tomatoes are heat loving plants that need lots of sun. But to set fruit the night and day temperatures need to fit in to a set range. Most types don't pollinate their flowers if:
1. the night temperatures are below 55 are above 72
2. the day tempeature is above 85

Planting seeds in April puts production in June/July which would be out of the temperature range. It's now almost Oct. so in a few weeks your plants should start setting fruit.

Good Luck