Kotlin vs Java

I
Java
final var order = Sandwich()
    .type("toastie")
    .bread("white")
    .fillings(List.of("Cheese", "Ham"))
    .dressings(List.of("Pepper", "Worcestershire sauce"))
    .side("Crisps")
    .makeMeASandwich()

System.out.println(ooSandwich.receipt())

// https://www.kotlindays.com/2019/12/02/days-of-kotlin-a-dsl-for-everyone/index.html
Kotlin
val dslSandwich = sandwich {
    with type "toasted"
    bread = "baguette"

    filling("cheese")
    filling("ham")
    filling("tomato")

    dressings {
        +"Basil"
        +"Pepper"
    }

    sideOrders {
        side("French Fries")
    }

}

println(dslSandwich.receipt())

// https://www.kotlindays.com/2019/12/02/days-of-kotlin-a-dsl-for-everyone/index.html
II
Java
Kotlin
val result = html {
    head {
        title { +"HTML encoding with Kotlin" }
    }
    body {
        h1 { +"HTML encoding with Kotlin" }
        p {
            +"this format can be used as an"
            +"alternative markup to HTML"
        }

        // an element with attributes and text content
        a(href = "http://jetbrains.com/kotlin") { +"Kotlin" }

        // mixed content
        p {
            +"This is some"
            b { +"mixed" }
            +"text. For more see the"
            a(href = "http://jetbrains.com/kotlin") {
                +"Kotlin"
            }
            +"project"
        }
        p {
            +"some text"
            ul {
                for (i in 1..5)
                    li { +"${i}*2 = ${i*2}" }
            }
        }
    }
}
III
Java
final var act = this;
final var layout = new LinearLayout(act);
layout.setOrientation(LinearLayout.VERTICAL);
final var name = new EditText(act);
final var button = new Button(act);
button.setText("Say Hello");
button.setOnClickListener(
    () -> {
        Toast.makeText(act, "Hello, " + name.text + "!", Toast.LENGTH_SHORT)
           .show()
}
layout.addView(name);
layout.addView(button);
Kotlin
verticalLayout {
    val name = editText()
    button("Say Hello") {
        onClick { toast("Hello, ${name.text}!") }
    }
}
IV
Java
Kotlin
override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)

    verticalLayout {
        padding = dip(30)
        editText {
            hint = "Name"
            textSize = 24f
        }
        editText {
            hint = "Password"
            textSize = 24f
        }
        button("Login") {
            textSize = 26f
        }
    }
}
V
Java
Kotlin
application.install(Routing) {
    get("/") {
        call.respondText("Hello, World!")
    }
    get("/bye") {
        call.respondText("Good bye, World!")
    }
}