Java Spark withColumn algebra by example

Spark (spark-core_2.13:3.3.2) and Java 11 here (very important, I need Java solutions please, not Scala!).

I am reading an Excel spreadsheet into a Dataset like so:

public void runSpark(MyDataJob dataJob, JavaSparkContext sparkContext) {

    SparkSession session = SparkSession.builder().sparkContext(sparkContext.sc()).getOrCreate();

    Dataset<Row> dataset = session.read()
        .format("com.crealytics.spark.excel")
        .option("dataAddress", "'My Sheet'!B3:C35")
        .option("header", "true")
        .option("treatEmptyValuesAsNulls", "true")
        .option("setErrorCellsToFallbackValues", "true")
        .option("usePlainNumberFormat", "false")
        .option("inferSchema", "true")
        .option("addColorColumns", "true")
        .option("timestampFormat", "MM-dd-yyyy HH:mm:ss")
        .option("maxRowsInMemory", 100)
        .option("maxByteArraySize", 2147483647)
        .option("tempFileThreshold", 10000000)
        .option("excerptSize", 10)
        .load(dataJob.getFileName());

    dataset.withColumn("CountDiff", ???);

}

The spreadsheet has 2 columns in it, NumFizz and NumBuzz, and hence, I'm guessing the Dataset has these columns as well. I need to add a new column that is the difference of these values in each row, meaning if a row's NumFizz value is 17, and its NumBuzz is 10, then its value in the new column should be 7. Unfortunately, since literally all the withColumn examples appear to be in Scala, I can't figure out how to do this in Java. I am also open to using Spark SQL if there's a simple solution using that as well. I just need a new CountDiff column added to my Dataset that has the difference of these two columns.

Can anyone nudge me in the right direction?

I tried to import the col functions and pass them in as args but the lack of viable Java examples is blocking me from making headway.

How about this:

dataset.withColumn("CountDiff", dataset.col("Numfizz").minus(dataset.col("Numbuzz")));

The Column.minus docs show examples of both Scala and Java usage, where scala applies it's magic operator conversion, and Java needs explicit function calls:

// Scala: The following selects the difference between people's height and their weight.
people.select( people("height") - people("weight") )

// Java:
people.select( people.col("height").minus(people.col("weight")) );

alternatively use SQL

You can also use SQL to perform express all the transformations you need:

dataset.createOrReplaceTempView("my_sheet")

session.sql("
SELECT
*, 
Numfizz - Numbuzz as CountDiff,
... -- other calculations you may need
FROM my_sheet 
").show();

When working with SQL you will may find the docs for SQL functions available in spark useful.