[SPARK-53183][SQL] Use Java Files.readString instead of o.a.s.sql.catalyst.util.fileToString

connector/docker-integration-tests/src/test/scala/org/apache/spark/sql/jdbc/querytest/CrossDbmsQueryTestSuite.scala

@@ -17,14 +17,14 @@
 package org.apache.spark.sql.jdbc
 
 import java.io.File
+import java.nio.file.Files
 import java.sql.ResultSet
 
 import scala.collection.mutable.ArrayBuffer
 import scala.util.control.NonFatal
 
 import org.apache.spark.sql.Row
 import org.apache.spark.sql.SQLQueryTestHelper
-import org.apache.spark.sql.catalyst.util.fileToString
 
 /**
  * This suite builds off of that to allow us to run other DBMS against the SQL test golden files (on
@@ -76,7 +76,7 @@ trait CrossDbmsQueryTestSuite extends DockerJDBCIntegrationSuite with SQLQueryTe
   }
 
   protected def runSqlTestCase(testCase: TestCase, listTestCases: Seq[TestCase]): Unit = {
-    val input = fileToString(new File(testCase.inputFile))
+    val input = Files.readString(new File(testCase.inputFile).toPath)
     val (comments, code) = splitCommentsAndCodes(input)
     val queries = getQueries(code, comments, listTestCases)
 
@@ -143,7 +143,7 @@ trait CrossDbmsQueryTestSuite extends DockerJDBCIntegrationSuite with SQLQueryTe
     // Read back the golden files.
     var curSegment = 0
     val expectedOutputs: Seq[QueryTestOutput] = {
-      val goldenOutput = fileToString(new File(testCase.resultFile))
+      val goldenOutput = Files.readString(new File(testCase.resultFile).toPath)
       val segments = goldenOutput.split("-- !query.*\n")
       outputs.map { output =>
         val result =

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/package.scala

@@ -18,7 +18,6 @@
 package org.apache.spark.sql.catalyst
 
 import java.io._
-import java.nio.charset.Charset
 import java.nio.charset.StandardCharsets.UTF_8
 
 import com.google.common.io.ByteStreams
@@ -48,15 +47,6 @@ package object util extends Logging {
     }
   }
 
-  def fileToString(file: File, encoding: Charset = UTF_8): String = {
-    val inStream = new FileInputStream(file)
-    try {
-      new String(ByteStreams.toByteArray(inStream), encoding)
-    } finally {
-      inStream.close()
-    }
-  }
-
   def resourceToBytes(
       resource: String,
       classLoader: ClassLoader = Utils.getSparkClassLoader): Array[Byte] = {

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/SQLKeywordSuite.scala

@@ -25,7 +25,6 @@ import scala.jdk.CollectionConverters._
 
 import org.apache.spark.SparkFunSuite
 import org.apache.spark.sql.catalyst.plans.SQLHelper
-import org.apache.spark.sql.catalyst.util.fileToString
 
 trait SQLKeywordUtils extends SparkFunSuite with SQLHelper {
 
@@ -38,7 +37,8 @@ trait SQLKeywordUtils extends SparkFunSuite with SQLHelper {
       getWorkspaceFilePath("sql", "api", "src", "main", "antlr4", "org",
         "apache", "spark", "sql", "catalyst", "parser", "SqlBaseLexer.g4").toFile
 
-    (fileToString(sqlBaseParserPath) + fileToString(sqlBaseLexerPath)).split("\n")
+    (Files.readString(sqlBaseParserPath.toPath) +
+      Files.readString(sqlBaseLexerPath.toPath)).split("\n")
   }
 
   // each element is an array of 4 string: the keyword name, reserve or not in Spark ANSI mode,
@@ -47,7 +47,7 @@ trait SQLKeywordUtils extends SparkFunSuite with SQLHelper {
     val docPath = {
       getWorkspaceFilePath("docs", "sql-ref-ansi-compliance.md").toFile
     }
-    fileToString(docPath).split("\n")
+    Files.readString(docPath.toPath).split("\n")
       .dropWhile(!_.startsWith("|Keyword|")).drop(2).takeWhile(_.startsWith("|"))
       .map(_.stripPrefix("|").split("\\|").map(_.trim))
   }

sql/core/src/test/scala/org/apache/spark/sql/ExpressionsSchemaSuite.scala

@@ -18,10 +18,11 @@
 package org.apache.spark.sql
 
 import java.io.File
+import java.nio.file.Files
 
 import scala.collection.mutable.ArrayBuffer
 
-import org.apache.spark.sql.catalyst.util.{fileToString, stringToFile}
+import org.apache.spark.sql.catalyst.util.stringToFile
 import org.apache.spark.sql.test.SharedSparkSession
 import org.apache.spark.tags.ExtendedSQLTest
 import org.apache.spark.util.Utils
@@ -165,7 +166,7 @@ class ExpressionsSchemaSuite extends QueryTest with SharedSparkSession {
     val outputSize = outputs.size
     val headerSize = header.size
     val expectedOutputs = {
-      val expectedGoldenOutput = fileToString(resultFile)
+      val expectedGoldenOutput = Files.readString(resultFile.toPath)
       val lines = expectedGoldenOutput.split("\n")
       val expectedSize = lines.size
 

sql/core/src/test/scala/org/apache/spark/sql/ICUCollationsMapSuite.scala

@@ -17,8 +17,10 @@
 
 package org.apache.spark.sql
 
+import java.nio.file.Files
+
 import org.apache.spark.SparkFunSuite
-import org.apache.spark.sql.catalyst.util.{fileToString, stringToFile, CollationFactory}
+import org.apache.spark.sql.catalyst.util.{stringToFile, CollationFactory}
 import org.apache.spark.util.Utils
 
 // scalastyle:off line.size.limit
@@ -61,7 +63,7 @@ class ICUCollationsMapSuite extends SparkFunSuite {
   }
 
   test("ICU locales map breaking change") {
-    val goldenLines = fileToString(collationsMapFile).split('\n')
+    val goldenLines = Files.readString(collationsMapFile.toPath).split('\n')
     val goldenRelevantLines = goldenLines.slice(4, goldenLines.length) // skip header
     val input = goldenRelevantLines.map(
       s => (s.split('|')(2).strip(), s.split('|')(1).strip().toInt))

sql/core/src/test/scala/org/apache/spark/sql/SQLQueryTestHelper.scala

@@ -18,6 +18,7 @@
 package org.apache.spark.sql
 
 import java.io.File
+import java.nio.file.Files
 
 import scala.collection.mutable.ArrayBuffer
 import scala.util.control.NonFatal
@@ -31,7 +32,6 @@ import org.apache.spark.sql.catalyst.SQLConfHelper
 import org.apache.spark.sql.catalyst.expressions.{CurrentDate, CurrentTime, CurrentTimestampLike, CurrentUser, Literal}
 import org.apache.spark.sql.catalyst.planning.PhysicalOperation
 import org.apache.spark.sql.catalyst.plans.logical._
-import org.apache.spark.sql.catalyst.util.fileToString
 import org.apache.spark.sql.execution.HiveResult.hiveResultString
 import org.apache.spark.sql.execution.SQLExecution
 import org.apache.spark.sql.execution.command.{DescribeColumnCommand, DescribeCommandBase}
@@ -410,7 +410,7 @@ trait SQLQueryTestHelper extends SQLConfHelper with Logging {
     val importedTestCaseName = comments.filter(_.startsWith("--IMPORT ")).map(_.substring(9))
     val importedCode = importedTestCaseName.flatMap { testCaseName =>
       allTestCases.find(_.name == testCaseName).map { testCase =>
-        val input = fileToString(new File(testCase.inputFile))
+        val input = Files.readString(new File(testCase.inputFile).toPath)
         val (_, code) = splitCommentsAndCodes(input)
         code
       }

sql/core/src/test/scala/org/apache/spark/sql/SQLQueryTestSuite.scala

@@ -19,6 +19,7 @@ package org.apache.spark.sql
 
 import java.io.File
 import java.net.URI
+import java.nio.file.Files
 import java.util.Locale
 
 import org.apache.spark.{SparkConf, TestUtils}
@@ -27,8 +28,8 @@ import org.apache.spark.sql.catalyst.parser.ParseException
 import org.apache.spark.sql.catalyst.plans.SQLHelper
 import org.apache.spark.sql.catalyst.plans.logical.{Command, LogicalPlan}
 import org.apache.spark.sql.catalyst.rules.RuleExecutor
-import org.apache.spark.sql.catalyst.util.{fileToString, stringToFile}
 import org.apache.spark.sql.catalyst.util.DateTimeConstants.NANOS_PER_SECOND
+import org.apache.spark.sql.catalyst.util.stringToFile
 import org.apache.spark.sql.execution.WholeStageCodegenExec
 import org.apache.spark.sql.internal.SQLConf
 import org.apache.spark.sql.internal.SQLConf.TimestampTypes
@@ -229,7 +230,7 @@ class SQLQueryTestSuite extends QueryTest with SharedSparkSession with SQLHelper
 
   /** Run a test case. */
   protected def runSqlTestCase(testCase: TestCase, listTestCases: Seq[TestCase]): Unit = {
-    val input = fileToString(new File(testCase.inputFile))
+    val input = Files.readString(new File(testCase.inputFile).toPath)
     val (comments, code) = splitCommentsAndCodes(input)
     val queries = getQueries(code, comments, listTestCases)
     val settings = getSparkSettings(comments)
@@ -639,7 +640,7 @@ class SQLQueryTestSuite extends QueryTest with SharedSparkSession with SQLHelper
       makeOutput: (String, Option[String], String) => QueryTestOutput): Unit = {
     // Read back the golden file.
     val expectedOutputs: Seq[QueryTestOutput] = {
-      val goldenOutput = fileToString(new File(resultFile))
+      val goldenOutput = Files.readString(new File(resultFile).toPath)
       val segments = goldenOutput.split("-- !query.*\n")
 
       val numSegments = outputs.map(_.numSegments).sum + 1

sql/core/src/test/scala/org/apache/spark/sql/TPCDSQueryTestSuite.scala

@@ -23,7 +23,7 @@ import java.nio.file.{Files, Paths}
 import scala.jdk.CollectionConverters._
 
 import org.apache.spark.{SparkConf, SparkContext}
-import org.apache.spark.sql.catalyst.util.{fileToString, resourceToString, stringToFile}
+import org.apache.spark.sql.catalyst.util.{resourceToString, stringToFile}
 import org.apache.spark.sql.internal.SQLConf
 import org.apache.spark.sql.test.TestSparkSession
 import org.apache.spark.tags.ExtendedSQLTest
@@ -130,7 +130,7 @@ class TPCDSQueryTestSuite extends QueryTest with TPCDSBase with SQLQueryTestHelp
 
         // Read back the golden file.
         val (expectedSchema, expectedOutput) = {
-          val goldenOutput = fileToString(goldenFile)
+          val goldenOutput = Files.readString(goldenFile.toPath)
           val segments = goldenOutput.split("-- !query.*\n")
 
           // query has 3 segments, plus the header

sql/hive-thriftserver/src/test/scala/org/apache/spark/sql/hive/thriftserver/ThriftServerQueryTestSuite.scala

@@ -18,6 +18,7 @@
 package org.apache.spark.sql.hive.thriftserver
 
 import java.io.File
+import java.nio.file.Files
 import java.sql.{SQLException, Statement, Timestamp}
 import java.util.{Locale, MissingFormatArgumentException}
 
@@ -27,7 +28,6 @@ import org.apache.spark.SparkException
 import org.apache.spark.internal.Logging
 import org.apache.spark.sql.SQLQueryTestSuite
 import org.apache.spark.sql.catalyst.analysis.NoSuchTableException
-import org.apache.spark.sql.catalyst.util.fileToString
 import org.apache.spark.sql.execution.HiveResult.{getBinaryFormatter, getTimeFormatters, toHiveString, BinaryFormatter, TimeFormatters}
 import org.apache.spark.sql.internal.SQLConf
 import org.apache.spark.sql.internal.SQLConf.TimestampTypes
@@ -151,7 +151,7 @@ class ThriftServerQueryTestSuite extends SQLQueryTestSuite with SharedThriftServ
 
       // Read back the golden file.
       val expectedOutputs: Seq[QueryTestOutput] = {
-        val goldenOutput = fileToString(new File(testCase.resultFile))
+        val goldenOutput = Files.readString(new File(testCase.resultFile).toPath)
         val segments = goldenOutput.split("-- !query.*\n")
 
         // each query has 3 segments, plus the header

sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveComparisonTest.scala

@@ -19,6 +19,7 @@ package org.apache.spark.sql.hive.execution
 
 import java.io._
 import java.nio.charset.StandardCharsets
+import java.nio.file.Files
 import java.util
 import java.util.Locale
 
@@ -322,7 +323,7 @@ abstract class HiveComparisonTest extends SparkFunSuite with BeforeAndAfterAll {
         val hiveCachedResults = hiveCacheFiles.flatMap { cachedAnswerFile =>
           logDebug(s"Looking for cached answer file $cachedAnswerFile.")
           if (cachedAnswerFile.exists) {
-            Some(fileToString(cachedAnswerFile))
+            Some(Files.readString(cachedAnswerFile.toPath))
           } else {
             logDebug(s"File $cachedAnswerFile not found")
             None

sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveQueryFileTest.scala

@@ -18,8 +18,7 @@
 package org.apache.spark.sql.hive.execution
 
 import java.io.File
-
-import org.apache.spark.sql.catalyst.util._
+import java.nio.file.Files
 
 /**
  * A framework for running the query tests that are listed as a set of text files.
@@ -67,7 +66,7 @@ abstract class HiveQueryFileTest extends HiveComparisonTest {
         realIncludeList.map(_.r.pattern.matcher(testCaseName).matches()).reduceLeft(_||_) ||
         runAll) {
         // Build a test case and submit it to scala test framework...
-        val queriesString = fileToString(testCaseFile)
+        val queriesString = Files.readString(testCaseFile.toPath)
         createQueryTest(testCaseName, queriesString, reset = true, tryWithoutResettingFirst = true)
       } else {
         // Only output warnings for the built in includeList as this clutters the output when the