Can't start `run-example.cmd`?

I downloaded Spark from the official site and ran the sample application. But I got the following error?

PS C: \ spark-2.1.0-bin-hadoop2.7>. \ Bin \ run-example.cmd
Exception in thread "main" java.lang.IllegalArgumentException: Missing application resource.
        at org.apache.spark.launcher.CommandBuilderUtils.checkArgument (CommandBuilderUtils.java:241)
        at org.apache.spark.launcher.SparkSubmitCommandBuilder.buildSparkSubmitArgs (SparkSubmitCommandBuilder.java:160)
        at org.apache.spark.launcher.SparkSubmitCommandBuilder.buildSparkSubmitCommand (SparkSubmitCommandBuilder.java:276)
        at org.apache.spark.launcher.SparkSubmitCommandBuilder.buildCommand (SparkSubmitCommandBuilder.java:151)
        at org.apache.spark.launcher.Main.main (Main.java:86)

Running in CMD

.

C: \ spark-2.1.0-bin-hadoop2.7> bin \ run-example.cmd
Exception in thread "main" java.lang.IllegalArgumentException: Missing application resource.
        at org.apache.spark.launcher.CommandBuilderUtils.checkArgument (CommandBuilderUtils.java:241)
        at org.apache.spark.launcher.SparkSubmitCommandBuilder.buildSparkSubmitArgs (SparkSubmitCommandBuilder.java:160)
        at org.apache.spark.launcher.SparkSubmitCommandBuilder.buildSparkSubmitCommand (SparkSubmitCommandBuilder.java:276)
        at org.apache.spark.launcher.SparkSubmitCommandBuilder.buildCommand (SparkSubmitCommandBuilder.java:151)
        at org.apache.spark.launcher.Main.main (Main.java:86)