Scala floating point arithmetic precision problem

During Spark development, when using java.math.BigDecimal directly for floating-point multiplication, there is still a lack of precision. But if it is pure JAVA, there is no such problem. Calling JAVA's BigDecimal in Scala has such a problem.

 

Accidentally found that Scala also implements scala.math.BigDecimal. If you switch to SCALA's own BigDecimal, there is no such problem.

 

I don't know the deep-seated reason, I'm throwing a brick here, if anyone knows, please enlighten me.

 

 

Below is the experimental code.

 

package com.cisco.test
import java.math.BigDecimal

object TestSyntax {
  def main(args: Array[String]): Unit = {
    val local_price=new BigDecimal(0.015)
    val exchange_rate = new BigDecimal(2)
    //0.02999999999999999888977697537484345957636833190917968750
    println(local_price.multiply(exchange_rate))

    //0.030
    import scala.math.BigDecimal
    println(BigDecimal("0.015") *  BigDecimal("2"))

    println(BigDecimal("0.0") *  BigDecimal("0.751879699"))
  }
}