int x = 5;
double y = 2.5;
double z = x + y; // x автоматически превращается в double

int i = (int) y; // i = 2, дробная часть отбрасывается

double x = Double.MAX_VALUE;
System.out.println(x * 2); // Infinity

public class Task260525 {
    public static void main(String[] args) {
        double d1 = 0.1 + 0.2;
        double d2 = 0.3;
        System.out.println(d1 == d2);
    }
}

<?xml version="1.0" encoding="UTF-8"?>  
<databaseChangeLog  
    xmlns="http://www.liquibase.org/xml/ns/dbchangelog"  
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
    xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog  
                        http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-4.6.xsd">  

    <changeSet id="1" author="alex">  
        <createTable tableName="users">  
            <column name="id" type="INT" autoIncrement="true">  
                <constraints primaryKey="true"/>  
            </column>  
            <column name="username" type="VARCHAR(50)"/>  
        </createTable>  
    </changeSet>  
</databaseChangeLog>  

databaseChangeLog:  
  - changeSet:  
      id: 1  
      author: alex  
      changes:  
        - createTable:  
            tableName: users  
            columns:  
              - column:  
                  name: id  
                  type: INT  
                  autoIncrement: true  
                  constraints:  
                    primaryKey: true  
              - column:  
                  name: username  
                  type: VARCHAR(50)  

--liquibase formatted sql  

--changeset alex:1  
CREATE TABLE users (  
    id INT PRIMARY KEY AUTO_INCREMENT,  
    username VARCHAR(50)  
);  

<dependency>  
    <groupId>org.liquibase</groupId>  
    <artifactId>liquibase-core</artifactId>  
    <version>4.20.0</version>  
</dependency>  

spring.liquibase.change-log=classpath:db/changelog/db.changelog-master.yaml  
spring.liquibase.url=jdbc:postgresql://localhost:5432/mydb  
spring.liquibase.user=user  
spring.liquibase.password=pass  

implementation 'org.liquibase:liquibase-core:4.20.0'

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;

public class Task270525 {
    public static void main(String[] args) {
        try (Connection conn = DriverManager.getConnection("jdbc:mysql://localhost/test", "user", "pass");
             Statement stmt = conn.createStatement()) {
            
            conn.setAutoCommit(false);
            stmt.executeUpdate("INSERT INTO users VALUES (1, 'John')");
            stmt.executeUpdate("INSERT INTO users VALUES (1, 'Mike')");
            conn.commit();
            
        } catch (
                SQLException e) {
            System.out.println("Error occurred");
        }
    }
}