add unitary test to the elements in the file org.apache.wayang.api.JavaPlanBuild...

add unitary test to the elements in the file org.apache.wayang.api.JavaPlanBuilder.scala

https://github.com/apache/incubator-wayang/blob/278cbdc4bd8e87863a7cb43bc68c52ca783039c0/wayang-api/wayang-api-scala-java/code/main/scala/org/apache/wayang/api/JavaPlanBuilder.scala#L21

```scala

*/

package org.apache.wayang.api
/**
* TODO: add unitary test to the elements in the file org.apache.wayang.api.JavaPlanBuilder.scala
* labels: unitary-test,todo
*/
import java.util.{Collection => JavaCollection}
import org.apache.commons.lang3.Validate
import org.apache.wayang.api.util.DataQuantaBuilderCache

```

f749b48e33189a4fec6508a1af48e238265907df

Start by reading wayang-api/wayang-api-scala-java/code/main/scala/org/apache/wayang/api/JavaPlanBuilder.scala at the referenced commit and identify the elements that need coverage. Check the repository's existing unit-test layout and conventions before adding tests. Done means the relevant JavaPlanBuilder elements have unit tests that pass.

Written by the indexing model from the issue text.