java-examples-for-kotlin-server-landing

// Initialization-on-demand holder implementation of a lazy singleton
public class Something {
    private Something() {}

    private static class LazyHolder {
        static final Something INSTANCE = new Something();
    }

    public static Something getInstance() {
        return LazyHolder.INSTANCE;
    }
}


// Filtering positive integers

 List<Integer> positiveNumbers = 
                      integers.stream().filter(i -> i > 0).collect(Collectors.toList());


// Simple POJO

public class CustomerX {
    private final String name;
    private final String email;
    private final String company;

    public CustomerX(@NotNull String name, @NotNull String email, @NotNull String company) {
        this.name = name;
        this.email = email;
        this.company = company;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        CustomerX customer = (CustomerX) o;
        return name.equals(customer.name) &&
                email.equals(customer.email) &&
                company.equals(customer.company);
    }

    @Override
    public int hashCode() {
        return Objects.hash(name, email, company);
    }
}