なぜKotlinを使うのですか?

Kotlinは

Kotlinの構築プロセス

Kotlin言語の特徴と優位性

//Kotlin
data class Person(val name: String, val age: Int)

//Java
public class Person {
	private String name;
	private int age;

	public Person(String name, int age) {
		this.name = name;
		this.age = age;
	}
	
	@Override 
	public int hashCode() {
		return super.hashCode();
	}

	@Override
	public boolean equals(Object obj) {
		return super.equals(obj);
	}

	@Override
	public String toString() {
		return "Person" + "name = " + name + "age = " + age;
	}
}

fun upload() { //callback
    loading.postValue(true)
    api.prepareUpload().enqueue(object : Callback<PrepareUploadResponse>{
        override fun onResponse(call: Call<PrepareUploadResponse>, response: Response<PrepareUploadResponse>) {
            if (response.isSuccessful) {
                val path = response.body()
                api.upload(path).enqueue(
                    object : Callback<UploadResponse>{
                        override fun onResponse(call: Call<UploadResponse>, response: Response<UploadResponse>) {
                            if (response.isSuccessful) {
                                loading.postValue(false)
                                successToast.postValue(true)
                            }
                        }
                        override fun onFailure(call: Call<PrepareUploadResponse>, t: Throwable) {
                            loading.postValue(false)
                            Log.d("")
                        }
                    }
                )
            }
        }
        override fun onFailure(call: Call<PrepareUploadResponse>, t: Throwable) {
            loading.postValue(false)
            Log.d("")
        }
    })
}

fun upload() { //coroutines
    try {
        val path = api.prepareUpload()
        val response = api.upload(path)
        loding.postValue(false)
        successToast.postValue(true)
    } catch (e: Exception) {
        loading.postValue(false)
        Log.d("")
    }
}