自定义source代码无法运行

package com.gaojingsi.scala

import org.apache.flink.streaming.api.functions.source.SourceFunction


class CustomIncreasementSource extends SourceFunction[Long] {
  var running = false
  var number = 1

  override def run(sourceContext: SourceFunction.SourceContext[Long]): Unit = {
    running = true
    while (running) {
      sourceContext.collect(number)
      number += 1
      Thread.sleep(1000)
    }
  }

  override def cancel(): Unit = {
    running = false
  }
}

package com.gaojingsi.scala

import org.apache.flink.streaming.api.scala.StreamExecutionEnvironment


object CustomSourceStudyScala {

  def main(args: Array[String]): Unit = {
    val streamExecutionEnvironment = StreamExecutionEnvironment.getExecutionEnvironment

    import org.apache.flink.api.scala._
    val ds = streamExecutionEnvironment.addSource(new CustomIncreasementSource).setParallelism(1)
    ds.print().setParallelism(1)

    streamExecutionEnvironment.execute("CustomSourceStudyScala")
  }

}

以上是我的自定义source代码，运行就报错：

我的依赖如下：

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请问可能的原因，嘿嘿，才疏学浅。