Why does the functional method take 2 parameters and the implementation takes one, but 2 arguments are specified in the usage?

Question

Java

There is this example code:

interface MyFunc<T> {
    boolean func(T a, T b);
}

class HighTemp {
    private int hTemp;

    public HighTemp(int hTemp) {
        this.hTemp = hTemp;
    }

    boolean sameTemp(HighTemp hTemp2) {
        return hTemp == hTemp2.hTemp;
    }

    boolean lessThanTemp(HighTemp hTemp2) {
        return hTemp < hTemp2.hTemp;
    }
}

class App {
    static <T> int counter(T[] vals, MyFunc<T> f, T v) {
        int count = 0;

        for (int i = 0; i < vals.length; i++) {
            if (f.func(vals[i], v)) {
                count++;
            }
        }

        return count;
    }

    public static void main(String[] args) {
        int count;

        HighTemp[] weekDayHighs = {
            new HighTemp(89),
            new HighTemp(82),
            new HighTemp(90),
            new HighTemp(89),
            new HighTemp(89),
            new HighTemp(91),
            new HighTemp(84),
            new HighTemp(83)
        };

        count = counter(weekDayHighs, HighTemp::sameTemp, new HighTemp(89));

        System.out.println("Дней, когда максимальная температура была 89: " + count);

        HighTemp[] weekDayHighs2 = {
            new HighTemp(32),
            new HighTemp(12),
            new HighTemp(24),
            new HighTemp(19),
            new HighTemp(18),
            new HighTemp(12),
            new HighTemp(-1),
            new HighTemp(13)
        };

        count = counter(weekDayHighs2, HighTemp::sameTemp, new HighTemp(12));

        System.out.println("Дней, когда максимальная температура была 12: " + count);

        count = counter(weekDayHighs, HighTemp::lessThanTemp, new HighTemp(89));

        System.out.println("Дней, когда максимальная температура была меньше 89: " + count);

        count = counter(weekDayHighs2, HighTemp::lessThanTemp, new HighTemp(19));

        System.out.println("Дней, когда максимальная температура была меньше 19: " + count);
    }
}

There is a generalized functional interface. It has a method with 2 parameters.
But why is counter passed a method (eg HighTemp::sameTemp) that takes 1 argument? According to the idea, this method is then written in the implementation of the interface in place of the func method, but it also has 2 parameters. Why then the func method then again takes 2 arguments if its implementation (for example HighTemp::sameTemp) takes only one??
I described the question as best I could, I myself do not understand anything. It does not reach what is happening in the code.

Answer 1

MyFunc<HighTemp> func = HighTemp::sameTemp;
the same as

MyFunc<HighTemp> func = new MyFunc<HighTemp>() {
    @Override
    boolean func(HighTemp a, HighTemp b) {
          a.sameTemp(b);
    }
};