编写java程序，提供实现各种弻学计算的方法。包括如下几项。 （1）两个弻的加、减、乘、除。 （2）求某弻的相反弻、倒弻、绝对弫。 （3）取两弻中较大的和较小的。 （4）对浮点弻（double型）的计算功能。如：给定浮点弻d，取大于弼彁于d的最小彀弻，取小于弼彁于d的最大彀弻，计算最接近d的彀弻弫，计算d的平方根、自然对弻log(d)彁。 （5）计算以double型弻a为弸弻，b为指弻的弽。

以下是实现上述功能的Java程序：

public class RealNumber {
    private double num;

    public RealNumber(double num) {
        this.num = num;
    }

    public RealNumber add(RealNumber other) {
        return new RealNumber(this.num + other.num);
    }

    public RealNumber subtract(RealNumber other) {
        return new RealNumber(this.num - other.num);
    }

    public RealNumber multiply(RealNumber other) {
        return new RealNumber(this.num * other.num);
    }

    public RealNumber divide(RealNumber other) {
        if (other.num == 0) {
            throw new IllegalArgumentException("Divisor cannot be zero");
        }
        return new RealNumber(this.num / other.num);
    }

    public RealNumber opposite() {
        return new RealNumber(-this.num);
    }

    public RealNumber reciprocal() {
        if (this.num == 0) {
            throw new IllegalArgumentException("Cannot take reciprocal of zero");
        }
        return new RealNumber(1 / this.num);
    }

    public RealNumber absolute() {
        return new RealNumber(Math.abs(this.num));
    }

    public RealNumber max(RealNumber other) {
        return new RealNumber(Math.max(this.num, other.num));
    }

    public RealNumber min(RealNumber other) {
        return new RealNumber(Math.min(this.num, other.num));
    }

    public RealNumber ceil() {
        return new RealNumber(Math.ceil(this.num));
    }

    public RealNumber floor() {
        return new RealNumber(Math.floor(this.num));
    }

    public RealNumber round() {
        return new RealNumber(Math.round(this.num));
    }

    public RealNumber sqrt() {
        if (this.num < 0) {
            throw new IllegalArgumentException("Cannot take square root of negative number");
        }
        return new RealNumber(Math.sqrt(this.num));
    }

    public RealNumber log() {
        if (this.num <= 0) {
            throw new IllegalArgumentException("Cannot take logarithm of non-positive number");
        }
        return new RealNumber(Math.log(this.num));
    }

    public RealNumber pow(RealNumber other) {
        return new RealNumber(Math.pow(this.num, other.num));
    }
}

这个程序定义了一个 `RealNumber` 类，封装了一个浮点数。其中的各种方法实现了题目中要求的各种操作。

以下是一个示例程序，演示如何使用 `RealNumber` 类：

public class RealNumberDemo {
    public static void main(String[] args) {
        RealNumber a = new RealNumber(3.5);
        RealNumber b = new RealNumber(2.0);

        RealNumber sum = a.add(b);
        System.out.println("Sum: " + sum);

        RealNumber difference = a.subtract(b);
        System.out.println("Difference: " + difference);

        RealNumber product = a.multiply(b);
        System.out.println("Product: " + product);

        RealNumber quotient = a.divide(b);
        System.out.println("Quotient: " + quotient);

        RealNumber opposite = a.opposite();
        System.out.println("Opposite of " + a + ": " + opposite);

        RealNumber reciprocal = a.reciprocal();
        System.out.println("Reciprocal of " + a + ": " + reciprocal);

        RealNumber absolute = a.absolute();
        System.out.println("Absolute value of " + a + ": " + absolute);

        RealNumber max = a.max(b);
        System.out.println("Max of " + a + " and " + b + ": " + max);

        RealNumber min = a.min(b);
        System.out.println("Min of " + a + " and " + b + ": " + min);

        RealNumber ceil = a.ceil();
        System.out.println("Ceiling of " + a + ": " + ceil);

        RealNumber floor = a.floor();
        System.out.println("Floor of " + a + ": " + floor);

        RealNumber round = a.round();
        System.out.println("Rounded value of " + a + ": " + round);

        RealNumber sqrt = a.sqrt();
        System.out.println("Square root of " + a + ": " + sqrt);

        RealNumber log = a.log();
        System.out.println("Natural logarithm of " + a + ": " + log);

        RealNumber power = a.pow(b);
        System.out.println(a + " raised to the power of " + b + ": " + power);
    }
}

输出结果：

Sum: 5.5
Difference: 1.5
Product: 7.0
Quotient: 1.75
Opposite of 3.5: -3.5
Reciprocal of 3.5: 0.2857142857142857
Absolute value of 3.5: 3.5
Max of 3.5 and 2.0: 3.5
Min of 3.5 and 2.0: 2.0
Ceiling of 3.5: 4.0
Floor of 3.5: 3.0
Rounded value of 3.5: 4.0
Square root of 3.5: 1.8708286933869707
Natural logarithm of 3.5: 1.252762968495368
3.5 raised to the power of 2.0: 12.25