写出Java10个【非检查】异常的代码实例

在Java中，非检查（Unchecked）异常也称为运行时异常，它们不是强制程序员处理的，因为它们通常表示程序逻辑错误而不是外部资源问题。以下是10个常见的非检查异常的例子，每个例子包含一个简短的代码片段：

1. `NullPointerException` (空指针异常)

public class Main {
    public static void main(String[] args) {
        String str = null;
        System.out.println(str.length());
    }
}

2. `ArithmeticException` (算术异常)

public class Main {
    public static void main(String[] args) {
        int a = 10;
        int b = 0;
        System.out.println(a / b);
    }
}

3. `ArrayIndexOutOfBoundsException` (数组下标越界异常)

public class Main {
    public static void main(String[] args) {
        int[] array = new int[5];
        System.out.println(array[10]);
    }
}

4. `IllegalArgumentException` (无效参数异常)

public class Main {
    public static void main(String[] args) {
        String invalidName = "";
        validateName(invalidName);
    }
    public static void validateName(String name) {
        if (name.isEmpty()) throw new IllegalArgumentException("Name cannot be empty");
    }
}

5. `IOException` (输入/输出异常)

public class Main {
    public static void main(String[] args) {
        try {
            File file = new File("non_existent_file.txt");
            BufferedReader reader = new BufferedReader(new FileReader(file));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }
}

6. `SQLException` (数据库连接异常)

public class Main {
    public static void main(String[] args) {
        try (Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "password")) {
            // Some SQL operation here that throws an exception
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

7. `RuntimeException` (运行时异常的超类)

public class Main {
    public static void main(String[] args) {
        throw new RuntimeException("Custom runtime exception");
    }
}

8. `NumberFormatException` (数字格式转换异常)

public class Main {
    public static void main(String[] args) {
        try {
            Integer.parseInt("abc");
        } catch (NumberFormatException e) {
            e.printStackTrace();
        }
    }
}

9. `IllegalStateException` (非法状态异常)

public class Main {
    private boolean isClosed = false;

    public void close() {
        if (isClosed) throw new IllegalStateException("Already closed");
        isClosed = true;
    }
}

10. `UnsupportedOperationException` (不支持的操作异常)

public class Main {
    public void methodNotSupported() {
        throw new UnsupportedOperationException("Method not supported");
    }
}