在Eclipse中调用Java中的Scala代码时出错

我想用Java调用以下Scala代码：

Scala代码

package calculate

import java.io._

class CalculationScala

object CalculationScala {
  def main(args: Array[String]) {
    def operate(a: Double, b: Double, op: (Double, Double) => Double): Double = (op(a, b))
    println(operate(5, 15, _-_))
  }
}

package calculate;

public class Calculation {
    public static void main(String[] args) {
        CalculationScala calculationScala = new CalculationScala();
        calculationScala.main(args);
    }
}

Java代码

package calculate

import java.io._

class CalculationScala

object CalculationScala {
  def main(args: Array[String]) {
    def operate(a: Double, b: Double, op: (Double, Double) => Double): Double = (op(a, b))
    println(operate(5, 15, _-_))
  }
}

package calculate;

public class Calculation {
    public static void main(String[] args) {
        CalculationScala calculationScala = new CalculationScala();
        calculationScala.main(args);
    }
}

但是出现了以下错误

错误

Exception in thread "main" java.lang.NoClassDefFoundError: scala/Function2
    at calculate.CalculationScala.main(CalculationScala.scala)
    at calculate.Calculation.main(Calculation.java:79)
Caused by: java.lang.ClassNotFoundException: scala.Function2
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
    ... 2 more

---

如何解决此问题？

运行时类路径上似乎缺少scala-library.jar。

谢谢您的回答。我已经下载并安装了它，并将位于/lib的

scala library.jar

添加到java项目的库java构建路径中，方法是将其添加为外部jar（右键单击java项目、java构建路径、库选项卡、添加外部jar…），这是正确的。我已经接受了答案，并投了赞成票。非常感谢。