利用JAVA语言设计一个简单的科学计算器，实现加减乘除及开根号、对数、平方、三角正/余弦、求倒数、进制转换的简单功能。

好的，以下是一个简单的Java科学计算器代码示例：

import java.util.Scanner;

public class ScientificCalculator {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.println("欢迎使用科学计算器！");

        while (true) {
            System.out.println("请选择要进行的操作：");
            System.out.println("1. 加法");
            System.out.println("2. 减法");
            System.out.println("3. 乘法");
            System.out.println("4. 除法");
            System.out.println("5. 开根号");
            System.out.println("6. 对数");
            System.out.println("7. 平方");
            System.out.println("8. 三角正/余弦");
            System.out.println("9. 求倒数");
            System.out.println("10. 进制转换");
            System.out.println("0. 退出");

            int choice = scanner.nextInt();

            if (choice == 0) {
                System.out.println("感谢使用科学计算器！");
                break;
            }

            switch (choice) {
                case 1:
                    System.out.println("请输入第一个数：");
                    double num1 = scanner.nextDouble();
                    System.out.println("请输入第二个数：");
                    double num2 = scanner.nextDouble();
                    System.out.println(num1 + " + " + num2 + " = " + (num1 + num2));
                    break;

                case 2:
                    System.out.println("请输入第一个数：");
                    num1 = scanner.nextDouble();
                    System.out.println("请输入第二个数：");
                    num2 = scanner.nextDouble();
                    System.out.println(num1 + " - " + num2 + " = " + (num1 - num2));
                    break;

                case 3:
                    System.out.println("请输入第一个数：");
                    num1 = scanner.nextDouble();
                    System.out.println("请输入第二个数：");
                    num2 = scanner.nextDouble();
                    System.out.println(num1 + " * " + num2 + " = " + (num1 * num2));
                    break;

                case 4:
                    System.out.println("请输入第一个数：");
                    num1 = scanner.nextDouble();
                    System.out.println("请输入第二个数：");
                    num2 = scanner.nextDouble();
                    if (num2 == 0) {
                        System.out.println("除数不能为0！");
                    } else {
                        System.out.println(num1 + " / " + num2 + " = " + (num1 / num2));
                    }
                    break;

                case 5:
                    System.out.println("请输入一个数：");
                    num1 = scanner.nextDouble();
                    if (num1 < 0) {
                        System.out.println("不能对负数进行开根号运算！");
                    } else {
                        System.out.println("√" + num1 + " = " + Math.sqrt(num1));
                    }
                    break;

                case 6:
                    System.out.println("请输入一个数：");
                    num1 = scanner.nextDouble();
                    if (num1 <= 0) {
                        System.out.println("对数必须大于0！");
                    } else {
                        System.out.println("log(" + num1 + ") = " + Math.log10(num1));
                    }
                    break;

                case 7:
                    System.out.println("请输入一个数：");
                    num1 = scanner.nextDouble();
                    System.out.println(num1 + "的平方是：" + Math.pow(num1, 2));
                    break;

                case 8:
                    System.out.println("请输入一个角度（0-360）：");
                    double angle = scanner.nextDouble();
                    System.out.println("sin(" + angle + ") = " + Math.sin(Math.toRadians(angle)));
                    System.out.println("cos(" + angle + ") = " + Math.cos(Math.toRadians(angle)));
                    break;

                case 9:
                    System.out.println("请输入一个非0数：");
                    num1 = scanner.nextDouble();
                    System.out.println("1/" + num1 + " = " + (1 / num1));
                    break;

                case 10:
                    System.out.println("请输入一个十进制数：");
                    int dec = scanner.nextInt();
                    System.out.println("转换成二进制：" + Integer.toBinaryString(dec));
                    System.out.println("转换成八进制：" + Integer.toOctalString(dec));
                    System.out.println("转换成十六进制：" + Integer.toHexString(dec));
                    break;

                default:
                    System.out.println("无效的操作！");
                    break;
            }
        }
    }
}

以上代码通过Scanner类获取用户输入的数字和操作符，然后使用switch语句进行计算，并将结果输出到控制台。除了基本的加减乘除运算外，还包括开根号、对数、平方、三角正/余弦、求倒数、进制转换等功能。请注意，上述代码只是一个简单的示例，没有包含太多的错误处理和完整的界面设计。