"the fruit is on table" is correct usage as fruit is both singular and plural
Almost. "Fruit" has uncountable (mass) noun and countable noun senses. To be plural would mean you can say "two fruit", which is not grammatical. The uncountable sense is used for single or multiple items of one kind of fruit, the countable sense is used when talking about multiple kinds of fruit. When enumerating the uncountable sense you must use another word to carry the plural such as "pieces of fruit".
Most native English speakers are not aware of the concept of mass nouns vs countable nouns unless they have taught English to speakers of other languages, or sometimes if they've studied foreign languages. People who speak English as a second language are more likely to know about this, depending on how they were taught. It's most common if their first language lacks plurality, as with many languages of East and Southeast Asia.
Here's a good article with answers specifically addressing the countable vs uncountable senses of "fruit".
I have taught English and never came across the concept of uncountable nouns until now, not even when I was learning French or German. But it makes sense. I just want to say that the countable sense is not mandatory even when talking of several varieties of fruit in English.
If there is a bowl containing some grapes, bananas, oranges and apples on a table, I would still say "The fruit is on the table." not "the fruits are on the table," I expect it is a matter of whether one is perceiving the contents of the bowl as a single kind of thing "fruit" or wishes to emphasize the presence of several varieties of fruit.
One would say, for example "All the fruits are on the table." meaning every kind of fruit being gathered/prepared.