Java | Фишки и трюки

final String pig = "length: 10";
final String dog = "length: " + pig.length();
System.out.println(pig == dog);

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
 
public class HelloWorld extends Application {
 
    @Override
    public void start(Stage primaryStage) {
        Button btn = new Button();
        btn.setText("Hello World");
 
        StackPane root = new StackPane();
        root.getChildren().add(btn);
 
        Scene scene = new Scene(root, 300, 250);
 
        primaryStage.setTitle("Hello World!");
        primaryStage.setScene(scene);
        primaryStage.show();
    }
 
    public static void main(String[] args) {
        launch(args);
    }
}

import java.util.regex.*;

public class RegexExample {
    public static void main(String[] args) {
        String text = "The cat in the hat";

        // Компилируем регулярное выражение
        Pattern pattern = Pattern.compile("\\bcat\\b");

        // Создаем Matcher, сравниваем его с текстом и выводим результат
        Matcher matcher = pattern.matcher(text);
        if (matcher.find()) {
            System.out.println("Найдено совпадение!");
        } else {
            System.out.println("Совпадений не найдено");
        }
    }
}

public class ShadesOfGray {
    public static void main(String[] args) {
        System.out.println(X.Y.Z);
    }
}

class X {
    static class Y {
        static String Z = "BLACK";
    }
    static C Y = new C();
}

class C {
    String Z = "WHITE";
}

public class MyClass {
    static {
        // Код статической инициализации
        System.out.println("Статическая инициализация MyClass");
    }

    public MyClass() {
        System.out.println("Конструктор MyClass");
    }
}

public class Start {
    public static void main(String[] args) {
        System.out.println("start");
        new MyClass();
        System.out.println("stop");
    }
}

start
Статическая инициализация MyClass
Конструктор MyClass
stop

SchedulerFactory schedulerFactory = new StdSchedulerFactory();
Scheduler scheduler = schedulerFactory.getScheduler();

public class MyJob implements Job {
  @Override
  public void execute(JobExecutionContext context) {
    System.out.println("Hello, Quartz!");
  }
}

JobDetail jobDetail = JobBuilder.newJob(MyJob.class)
    .withIdentity("myJob")
    .build();

Trigger trigger = TriggerBuilder.newTrigger()
    .withIdentity("myTrigger")
    .startNow()
    .withSchedule(SimpleScheduleBuilder.simpleSchedule()
        .withIntervalInSeconds(10)
        .repeatForever())
    .build();

scheduler.scheduleJob(jobDetail, trigger);
scheduler.start();

public class MyClass implements Cloneable {
    private int value;
    
    // Конструкторы и методы класса
    
    @Override
    public Object clone() throws CloneNotSupportedException {
        return super.clone();
    }
}

Frame frame = new Frame("Название окна");
frame.setSize(400, 300);
frame.setVisible(true);

JFrame frame = new JFrame("Название окна");
frame.setSize(400, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);

Button button = new Button("Нажми меня");
frame.add(button);

JButton button = new JButton("Нажми меня");
frame.add(button);

TextField textField = new TextField("Введите текст");
frame.add(textField);

JTextField textField = new JTextField("Введите текст");
frame.add(textField);

button.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        System.out.println("Кнопка была нажата");
    }
});

Tomcat tomcat = new Tomcat();
tomcat.setPort(8080);
tomcat.addWebapp("/myapp", new File("src/main/webapp/").getAbsolutePath());
tomcat.addServlet("/myservlet", "MyServlet", MyServlet.class.getName());
tomcat.start();

<dependency>
 <groupId>org.apache.tomcat.embed</groupId>
 <artifactId>tomcat-embed-core</artifactId>
 <version>11.0.0-M18</version>
</dependency>
<dependency>
 <groupId>org.apache.tomcat.embed</groupId>
 <artifactId>tomcat-embed-jasper</artifactId>
 <version>11.0.0-M18</version>
</dependency>
<dependency>
 <groupId>org.apache.tomcat</groupId>
 <artifactId>tomcat-jasper</artifactId>
 <version>11.0.0-M18</version>
</dependency>
<dependency>
 <groupId>org.apache.tomcat</groupId>
 <artifactId>tomcat-jasper-el</artifactId>
 <version>11.0.0-M18</version>
</dependency>
<dependency>
 <groupId>org.apache.tomcat</groupId>
 <artifactId>tomcat-jsp-api</artifactId>
 <version>11.0.0-M18</version>
</dependency>