Here are example codes in Java:

public class HelloWorld {

    public static void main(String[] args) {

        System.out.println("Hello, World!");

    }

}

int age = 25;

double salary = 50000.50;

char grade = 'A';

String name = "John";

boolean isEmployed = true;

int number = 10;

if (number > 0) {

    System.out.println("Number is positive.");

} else {

    System.out.println("Number is negative.");

}

for (int i = 1; i <= 5; i++) {

    System.out.println("Iteration: " + i);

}

int[] numbers = {1, 2, 3, 4, 5};

for (int i = 0; i < numbers.length; i++) {

    System.out.println(numbers[i]);

}

class Person {

    String name;

    int age;

    void displayInfo() {

        System.out.println("Name: " + name);

        System.out.println("Age: " + age);

    }

}

Person person1 = new Person();

person1.name = "Alice";

person1.age = 30;

person1.displayInfo();

try {

    int result = 10 / 0;

} catch (ArithmeticException e) {

    System.out.println("Error: " + e.getMessage());

}

class Vehicle {

    void displayInfo() {

        System.out.println("This is a vehicle.");

    }

}

class Car extends Vehicle {

    void displayInfo() {

        System.out.println("This is a car.");

    }

}

Car car = new Car();

car.displayInfo(); // Output: This is a car.