Time magics with Kotlin

time.kt

import java.util.Date
import kotlin.concurrent.*

fun at(date: Date, func: () -> Unit) {
    val waitTime = date.getTime() - Date().getTime()
    thread {
        Thread.sleep(waitTime)
        func()
    }
}

fun every(interval: TimeSpan, func: () -> Unit) {
    thread {
        while (true) {
            Thread.sleep(interval.milliseconds)
            func()
        }
    }
}

data class TimeSpan(val milliseconds: Long) {
    fun plus(other: TimeSpan) = TimeSpan(milliseconds + other.milliseconds)
    fun plus(other: Date) = Date(milliseconds + other.getTime())
    fun and(other: TimeSpan): TimeSpan = this + other
    fun from(date: Date): Date = this + date
}

val Int.seconds: TimeSpan get() = TimeSpan(this * 1000L)
val Int.second: TimeSpan get() = this.seconds

val Int.minutes: TimeSpan get() = TimeSpan(this * 60000L)
val Int.minute: TimeSpan get() = this.minutes

val now: Date get() = Date()

fun main(args: Array<String>) {
    at (1.minute and 10.seconds from now) {
        println("Excellent.")
    }

    every (15.seconds) {
        println("Beep.")
    }

    println("Blocking...")
    while (true) {}
}

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( ͝° ͜ʖ ͝°)

is there any problem with while (true) {} line. will it eat CPU resources ?