[jvm-packages] clean up example (#10618)

jvm-packages/xgboost4j-example/src/main/scala/ml/dmlc/xgboost4j/scala/example/BasicWalkThrough.scala

@@ -1,5 +1,5 @@
 /*
- Copyright (c) 2014-2023 by Contributors
+ Copyright (c) 2014-2024 by Contributors
 
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -23,7 +23,7 @@ import scala.collection.mutable
 
 import ml.dmlc.xgboost4j.java.{DMatrix => JDMatrix}
 import ml.dmlc.xgboost4j.java.example.util.DataLoader
-import ml.dmlc.xgboost4j.scala.{XGBoost, DMatrix}
+import ml.dmlc.xgboost4j.scala.{DMatrix, XGBoost}
 
 object BasicWalkThrough {
   def saveDumpModel(modelPath: String, modelInfos: Array[String]): Unit = {

jvm-packages/xgboost4j-example/src/main/scala/ml/dmlc/xgboost4j/scala/example/BoostFromPrediction.scala

@@ -1,5 +1,5 @@
 /*
- Copyright (c) 2014 by Contributors
+ Copyright (c) 2014-2024 by Contributors
 
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -18,7 +18,8 @@ package ml.dmlc.xgboost4j.scala.example
 
 import scala.collection.mutable
 
-import ml.dmlc.xgboost4j.scala.{XGBoost, DMatrix}
+import ml.dmlc.xgboost4j.scala.{DMatrix, XGBoost}
+
 
 object BoostFromPrediction {
   def main(args: Array[String]): Unit = {
@@ -48,6 +49,6 @@ object BoostFromPrediction {
     testMat.setBaseMargin(testPred)
 
     System.out.println("result of running from initial prediction")
-    val booster2 = XGBoost.train(trainMat, params.toMap, 1, watches.toMap, null, null)
+    XGBoost.train(trainMat, params.toMap, 1, watches.toMap, null, null)
   }
 }

jvm-packages/xgboost4j-example/src/main/scala/ml/dmlc/xgboost4j/scala/example/CrossValidation.scala

@@ -17,7 +17,7 @@ package ml.dmlc.xgboost4j.scala.example
 
 import scala.collection.mutable
 
-import ml.dmlc.xgboost4j.scala.{XGBoost, DMatrix}
+import ml.dmlc.xgboost4j.scala.{DMatrix, XGBoost}
 
 object CrossValidation {
   def main(args: Array[String]): Unit = {
@@ -40,7 +40,6 @@ object CrossValidation {
     // set additional eval_metrics
     val metrics: Array[String] = null
 
-    val evalHist: Array[String] =
     XGBoost.crossValidation(trainMat, params.toMap, round, nfold, metrics)
   }
 }

jvm-packages/xgboost4j-example/src/main/scala/ml/dmlc/xgboost4j/scala/example/CustomObjective.scala

@@ -1,5 +1,5 @@
 /*
- Copyright (c) 2014 by Contributors
+ Copyright (c) 2014-2024 by Contributors
 
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -18,9 +18,10 @@ package ml.dmlc.xgboost4j.scala.example
 import scala.collection.mutable
 import scala.collection.mutable.ListBuffer
 
+import org.apache.commons.logging.{Log, LogFactory}
+
 import ml.dmlc.xgboost4j.java.XGBoostError
-import ml.dmlc.xgboost4j.scala.{XGBoost, DMatrix, EvalTrait, ObjectiveTrait}
+import ml.dmlc.xgboost4j.scala.{DMatrix, EvalTrait, ObjectiveTrait, XGBoost}
-import org.apache.commons.logging.{LogFactory, Log}
 
 /**
  * an example user define objective and eval
@@ -150,7 +151,7 @@ object CustomObjective {
 
     val round = 2
     // train a model
-    val booster = XGBoost.train(trainMat, params.toMap, round, watches.toMap)
+    XGBoost.train(trainMat, params.toMap, round, watches.toMap)
     XGBoost.train(trainMat, params.toMap, round, watches.toMap,
       obj = new LogRegObj, eval = new EvalError)
   }

jvm-packages/xgboost4j-example/src/main/scala/ml/dmlc/xgboost4j/scala/example/ExternalMemory.scala

@@ -1,5 +1,5 @@
 /*
- Copyright (c) 2014 by Contributors
+ Copyright (c) 2014-2024 by Contributors
 
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -18,7 +18,7 @@ package ml.dmlc.xgboost4j.scala.example
 
 import scala.collection.mutable
 
-import ml.dmlc.xgboost4j.scala.{XGBoost, DMatrix}
+import ml.dmlc.xgboost4j.scala.{DMatrix, XGBoost}
 
 object ExternalMemory {
   def main(args: Array[String]): Unit = {
@@ -54,6 +54,6 @@ object ExternalMemory {
     testMat.setBaseMargin(testPred)
 
     System.out.println("result of running from initial prediction")
-    val booster2 = XGBoost.train(trainMat, params.toMap, 1, watches.toMap)
+    XGBoost.train(trainMat, params.toMap, 1, watches.toMap)
   }
 }

jvm-packages/xgboost4j-example/src/main/scala/ml/dmlc/xgboost4j/scala/example/GeneralizedLinearModel.scala

@@ -1,5 +1,5 @@
 /*
- Copyright (c) 2014 by Contributors
+ Copyright (c) 2014-2024 by Contributors
 
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -17,7 +17,7 @@ package ml.dmlc.xgboost4j.scala.example
 
 import scala.collection.mutable
 
-import ml.dmlc.xgboost4j.scala.{XGBoost, DMatrix}
+import ml.dmlc.xgboost4j.scala.{DMatrix, XGBoost}
 import ml.dmlc.xgboost4j.scala.example.util.CustomEval
 
 
@@ -51,7 +51,6 @@ object GeneralizedLinearModel {
     watches += "train" -> trainMat
     watches += "test" -> testMat
 
-    val round = 4
     val booster = XGBoost.train(trainMat, params.toMap, 1, watches.toMap)
     val predicts = booster.predict(testMat)
     val eval = new CustomEval

jvm-packages/xgboost4j-example/src/main/scala/ml/dmlc/xgboost4j/scala/example/PredictFirstNTree.scala

@@ -1,5 +1,5 @@
 /*
- Copyright (c) 2014 by Contributors
+ Copyright (c) 2014-2024 by Contributors
 
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -17,8 +17,8 @@ package ml.dmlc.xgboost4j.scala.example
 
 import scala.collection.mutable
 
+import ml.dmlc.xgboost4j.scala.{DMatrix, XGBoost}
 import ml.dmlc.xgboost4j.scala.example.util.CustomEval
-import ml.dmlc.xgboost4j.scala.{XGBoost, DMatrix}
 
 object PredictFirstNTree {
 

jvm-packages/xgboost4j-example/src/main/scala/ml/dmlc/xgboost4j/scala/example/PredictLeafIndices.scala

@@ -1,5 +1,5 @@
 /*
- Copyright (c) 2014 by Contributors
+ Copyright (c) 2014-2024 by Contributors
 
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -16,11 +16,9 @@
 
 package ml.dmlc.xgboost4j.scala.example
 
-import java.util
-
 import scala.collection.mutable
 
-import ml.dmlc.xgboost4j.scala.{XGBoost, DMatrix}
+import ml.dmlc.xgboost4j.scala.{DMatrix, XGBoost}
 
 object PredictLeafIndices {
 
@@ -49,7 +47,7 @@ object PredictLeafIndices {
 
     // predict all trees
     val leafIndex2 = booster.predictLeaf(testMat, 0)
-    for (leafs <- leafIndex) {
+    for (leafs <- leafIndex2) {
       println(java.util.Arrays.toString(leafs))
     }
   }

jvm-packages/xgboost4j-example/src/main/scala/ml/dmlc/xgboost4j/scala/example/flink/DistTrainWithFlink.scala

@@ -1,5 +1,5 @@
 /*
- Copyright (c) 2014 - 2023 by Contributors
+ Copyright (c) 2014 - 2024 by Contributors
 
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -17,12 +17,14 @@ package ml.dmlc.xgboost4j.scala.example.flink
 
 import java.lang.{Double => JDouble, Long => JLong}
 import java.nio.file.{Path, Paths}
-import org.apache.flink.api.java.tuple.{Tuple13, Tuple2}
+
-import org.apache.flink.api.java.{DataSet, ExecutionEnvironment}
-import org.apache.flink.ml.linalg.{Vector, Vectors}
-import ml.dmlc.xgboost4j.java.flink.{XGBoost, XGBoostModel}
 import org.apache.flink.api.common.typeinfo.{TypeHint, TypeInformation}
+import org.apache.flink.api.java.{DataSet, ExecutionEnvironment}
+import org.apache.flink.api.java.tuple.{Tuple13, Tuple2}
 import org.apache.flink.api.java.utils.DataSetUtils
+import org.apache.flink.ml.linalg.{Vector, Vectors}
+
+import ml.dmlc.xgboost4j.java.flink.{XGBoost, XGBoostModel}
 
 
 object DistTrainWithFlink {

jvm-packages/xgboost4j-example/src/main/scala/ml/dmlc/xgboost4j/scala/example/spark/SparkMLlibPipeline.scala

@@ -22,6 +22,7 @@ import org.apache.spark.ml.feature._
 import org.apache.spark.ml.tuning._
 import org.apache.spark.sql.{DataFrame, SparkSession}
 import org.apache.spark.sql.types._
+
 import ml.dmlc.xgboost4j.scala.spark.{XGBoostClassificationModel, XGBoostClassifier}
 
 // this example works with Iris dataset (https://archive.ics.uci.edu/ml/datasets/iris)
@@ -87,11 +88,9 @@ object SparkMLlibPipeline {
         "max_depth" -> 2,
         "objective" -> "multi:softprob",
         "num_class" -> 3,
-        "num_round" -> 100,
-        "num_workers" -> numWorkers,
         "device" -> device
       )
-    )
+    ).setNumRound(10).setNumWorkers(numWorkers)
     booster.setFeaturesCol("features")
     booster.setLabelCol("classIndex")
     val labelConverter = new IndexToString()

jvm-packages/xgboost4j-example/src/main/scala/ml/dmlc/xgboost4j/scala/example/spark/SparkTraining.scala

@@ -16,11 +16,13 @@
 
 package ml.dmlc.xgboost4j.scala.example.spark
 
-import ml.dmlc.xgboost4j.scala.spark.XGBoostClassifier
 import org.apache.spark.ml.feature.{StringIndexer, VectorAssembler}
 import org.apache.spark.sql.{DataFrame, SparkSession}
 import org.apache.spark.sql.types.{DoubleType, StringType, StructField, StructType}
 
+import ml.dmlc.xgboost4j.scala.spark.XGBoostClassifier
+
+
 // this example works with Iris dataset (https://archive.ics.uci.edu/ml/datasets/iris)
 object SparkTraining {
 
@@ -78,13 +80,13 @@ private[spark] def run(spark: SparkSession, inputPath: String,
       "max_depth" -> 2,
       "objective" -> "multi:softprob",
       "num_class" -> 3,
-      "num_round" -> 100,
+      "eval_sets" -> Map("eval1" -> eval1, "eval2" -> eval2),
-      "num_workers" -> numWorkers,
+      "device" -> device)
-      "device" -> device,
-      "eval_sets" -> Map("eval1" -> eval1, "eval2" -> eval2))
     val xgbClassifier = new XGBoostClassifier(xgbParam).
       setFeaturesCol("features").
       setLabelCol("classIndex")
+      .setNumWorkers(numWorkers)
+      .setNumRound(10)
     val xgbClassificationModel = xgbClassifier.fit(train)
     xgbClassificationModel.transform(test)
   }

jvm-packages/xgboost4j-example/src/main/scala/ml/dmlc/xgboost4j/scala/example/util/CustomEval.scala

@@ -15,9 +15,10 @@
  */
 package ml.dmlc.xgboost4j.scala.example.util
 
+import org.apache.commons.logging.{Log, LogFactory}
+
 import ml.dmlc.xgboost4j.java.XGBoostError
 import ml.dmlc.xgboost4j.scala.{DMatrix, EvalTrait}
-import org.apache.commons.logging.{Log, LogFactory}
 
 class CustomEval extends EvalTrait {
   private val logger: Log = LogFactory.getLog(classOf[CustomEval])

jvm-packages/xgboost4j-example/src/test/scala/ml/dmlc/xgboost4j/java/example/flink/DistTrainWithFlinkExampleTest.scala

@@ -1,5 +1,5 @@
 /*
- Copyright (c) 2014-2023 by Contributors
+ Copyright (c) 2014-2024 by Contributors
 
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -15,12 +15,13 @@
  */
 package ml.dmlc.xgboost4j.java.example.flink
 
+import java.nio.file.Paths
+
 import org.apache.flink.api.java.ExecutionEnvironment
 import org.scalatest.Inspectors._
 import org.scalatest.funsuite.AnyFunSuite
 import org.scalatest.matchers.should.Matchers._
 
-import java.nio.file.Paths
 
 class DistTrainWithFlinkExampleTest extends AnyFunSuite {
   private val parentPath = Paths.get("../../").resolve("demo").resolve("data")

jvm-packages/xgboost4j-example/src/test/scala/ml/dmlc/xgboost4j/scala/example/flink/DistTrainWithFlinkSuite.scala

@@ -15,14 +15,15 @@
  */
 package ml.dmlc.xgboost4j.scala.example.flink
 
+import java.nio.file.Paths
+
+import scala.jdk.CollectionConverters._
+
 import org.apache.flink.api.java.ExecutionEnvironment
 import org.scalatest.Inspectors._
 import org.scalatest.funsuite.AnyFunSuite
 import org.scalatest.matchers.should.Matchers._
 
-import java.nio.file.Paths
-import scala.jdk.CollectionConverters._
-
 class DistTrainWithFlinkSuite extends AnyFunSuite {
   private val parentPath = Paths.get("../../").resolve("demo").resolve("data")
   private val data = parentPath.resolve("veterans_lung_cancer.csv")

jvm-packages/xgboost4j-example/src/test/scala/ml/dmlc/xgboost4j/scala/example/spark/SparkExamplesTest.scala

@@ -1,5 +1,5 @@
 /*
- Copyright (c) 2014-2023 by Contributors
+ Copyright (c) 2014-2024 by Contributors
 
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -15,16 +15,18 @@
  */
 package ml.dmlc.xgboost4j.scala.example.spark
 
+
+import java.io.File
+import java.nio.file.{Files, StandardOpenOption}
+
+import scala.jdk.CollectionConverters._
+import scala.util.{Random, Try}
+
 import org.apache.spark.sql.SparkSession
 import org.scalatest.BeforeAndAfterAll
 import org.scalatest.funsuite.AnyFunSuite
 import org.slf4j.LoggerFactory
 
-import java.io.File
-import java.nio.file.{Files, StandardOpenOption}
-import scala.jdk.CollectionConverters._
-import scala.util.{Random, Try}
-
 class SparkExamplesTest extends AnyFunSuite with BeforeAndAfterAll {
   private val logger = LoggerFactory.getLogger(classOf[SparkExamplesTest])
   private val random = new Random(42)