[SPARK-53152][CORE][K8S][YARN] Use Java Files.readString instead of Files.asCharSource

core/src/test/java/test/org/apache/spark/JavaAPISuite.java

@@ -960,7 +960,7 @@ public void textFiles() throws IOException {
     rdd.saveAsTextFile(outputDir);
     // Read the plain text file and check it's OK
     File outputFile = new File(outputDir, "part-00000");
-    String content = Files.asCharSource(outputFile, StandardCharsets.UTF_8).read();
+    String content = java.nio.file.Files.readString(outputFile.toPath());
     assertEquals("1\n2\n3\n4\n", content);
     // Also try reading it in as a text file RDD
     List<String> expected = Arrays.asList("1", "2", "3", "4");

core/src/test/scala/org/apache/spark/deploy/history/EventLogFileReadersSuite.scala

@@ -19,10 +19,10 @@ package org.apache.spark.deploy.history
 
 import java.io.{ByteArrayInputStream, ByteArrayOutputStream, File}
 import java.net.URI
-import java.nio.charset.StandardCharsets
+import java.nio.file.Files
 import java.util.zip.{ZipInputStream, ZipOutputStream}
 
-import com.google.common.io.{ByteStreams, Files}
+import com.google.common.io.ByteStreams
 import org.apache.hadoop.conf.Configuration
 import org.apache.hadoop.fs.Path
 import org.scalatest.BeforeAndAfter
@@ -220,8 +220,8 @@ class SingleFileEventLogFileReaderSuite extends EventLogFileReadersSuite {
 
       val entry = is.getNextEntry
       assert(entry != null)
-      val actual = new String(ByteStreams.toByteArray(is), StandardCharsets.UTF_8)
-      val expected = Files.asCharSource(new File(logPath.toString), StandardCharsets.UTF_8).read()
+      val actual = ByteStreams.toByteArray(is)
+      val expected = Files.readAllBytes(new File(logPath.toString).toPath)
       assert(actual === expected)
       assert(is.getNextEntry === null)
     }
@@ -367,9 +367,8 @@ class RollingEventLogFilesReaderSuite extends EventLogFileReadersSuite {
           val fileName = entry.getName.stripPrefix(logPath.getName + "/")
           assert(allFileNames.contains(fileName))
 
-          val actual = new String(ByteStreams.toByteArray(is), StandardCharsets.UTF_8)
-          val expected = Files.asCharSource(
-            new File(logPath.toString, fileName), StandardCharsets.UTF_8).read()
+          val actual = ByteStreams.toByteArray(is)
+          val expected = Files.readAllBytes(new File(logPath.toString, fileName).toPath)
           assert(actual === expected)
         }
       }

core/src/test/scala/org/apache/spark/deploy/history/FsHistoryProviderSuite.scala

@@ -708,8 +708,7 @@ abstract class FsHistoryProviderSuite extends SparkFunSuite with Matchers with P
       while (entry != null) {
         val actual = new String(ByteStreams.toByteArray(inputStream), StandardCharsets.UTF_8)
         val expected =
-          Files.asCharSource(logs.find(_.getName == entry.getName).get, StandardCharsets.UTF_8)
-            .read()
+          java.nio.file.Files.readString(logs.find(_.getName == entry.getName).get.toPath)
         actual should be (expected)
         totalEntries += 1
         entry = inputStream.getNextEntry

core/src/test/scala/org/apache/spark/deploy/history/HistoryServerSuite.scala

@@ -19,12 +19,13 @@ package org.apache.spark.deploy.history
 import java.io.{File, FileInputStream, FileWriter, InputStream, IOException}
 import java.net.{HttpURLConnection, URI, URL}
 import java.nio.charset.StandardCharsets
+import java.nio.file.Files
 import java.util.zip.ZipInputStream
 
 import scala.concurrent.duration._
 import scala.jdk.CollectionConverters._
 
-import com.google.common.io.{ByteStreams, Files}
+import com.google.common.io.ByteStreams
 import jakarta.servlet._
 import jakarta.servlet.http.{HttpServletRequest, HttpServletRequestWrapper, HttpServletResponse}
 import org.apache.hadoop.fs.{FileStatus, FileSystem, Path}
@@ -308,7 +309,7 @@ abstract class HistoryServerSuite extends SparkFunSuite with BeforeAndAfter with
         val expectedFile = {
           new File(logDir, entry.getName)
         }
-        val expected = Files.asCharSource(expectedFile, StandardCharsets.UTF_8).read()
+        val expected = Files.readString(expectedFile.toPath)
         val actual = new String(ByteStreams.toByteArray(zipStream), StandardCharsets.UTF_8)
         actual should be (expected)
         filesCompared += 1

core/src/test/scala/org/apache/spark/util/FileAppenderSuite.scala

@@ -58,7 +58,7 @@ class FileAppenderSuite extends SparkFunSuite with BeforeAndAfter {
     val appender = new FileAppender(inputStream, testFile)
     inputStream.close()
     appender.awaitTermination()
-    assert(Files.asCharSource(testFile, StandardCharsets.UTF_8).read() === header + testString)
+    assert(java.nio.file.Files.readString(testFile.toPath) === header + testString)
   }
 
   test("SPARK-35027: basic file appender - close stream") {
@@ -392,7 +392,7 @@ class FileAppenderSuite extends SparkFunSuite with BeforeAndAfter {
           Utils.closeQuietly(inputStream)
         }
       } else {
-        Files.asCharSource(file, StandardCharsets.UTF_8).read()
+        java.nio.file.Files.readString(file.toPath)
       }
     }.mkString("")
     assert(allText === expectedText)

resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/SparkKubernetesClientFactory.scala

@@ -17,10 +17,9 @@
 package org.apache.spark.deploy.k8s
 
 import java.io.File
-import java.nio.charset.StandardCharsets
+import java.nio.file.Files
 
 import com.fasterxml.jackson.databind.ObjectMapper
-import com.google.common.io.Files
 import io.fabric8.kubernetes.client.{ConfigBuilder, KubernetesClient, KubernetesClientBuilder}
 import io.fabric8.kubernetes.client.Config.KUBERNETES_REQUEST_RETRY_BACKOFFLIMIT_SYSTEM_PROPERTY
 import io.fabric8.kubernetes.client.Config.autoConfigure
@@ -98,8 +97,7 @@ object SparkKubernetesClientFactory extends Logging {
       .withOption(oauthTokenValue) {
         (token, configBuilder) => configBuilder.withOauthToken(token)
       }.withOption(oauthTokenFile) {
-        (file, configBuilder) =>
-            configBuilder.withOauthToken(Files.asCharSource(file, StandardCharsets.UTF_8).read())
+        (file, configBuilder) => configBuilder.withOauthToken(Files.readString(file.toPath))
       }.withOption(caCertFile) {
         (file, configBuilder) => configBuilder.withCaCertFile(file)
       }.withOption(clientKeyFile) {

resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/features/HadoopConfDriverFeatureStep.scala

@@ -17,11 +17,10 @@
 package org.apache.spark.deploy.k8s.features
 
 import java.io.File
-import java.nio.charset.StandardCharsets
+import java.nio.file.Files
 
 import scala.jdk.CollectionConverters._
 
-import com.google.common.io.Files
 import io.fabric8.kubernetes.api.model._
 
 import org.apache.spark.deploy.k8s.{KubernetesConf, KubernetesUtils, SparkPod}
@@ -116,7 +115,7 @@ private[spark] class HadoopConfDriverFeatureStep(conf: KubernetesConf)
   override def getAdditionalKubernetesResources(): Seq[HasMetadata] = {
     if (confDir.isDefined) {
       val fileMap = confFiles.map { file =>
-        (file.getName(), Files.asCharSource(file, StandardCharsets.UTF_8).read())
+        (file.getName(), Files.readString(file.toPath))
       }.toMap.asJava
 
       Seq(new ConfigMapBuilder()

resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/features/KerberosConfDriverFeatureStep.scala

@@ -17,7 +17,6 @@
 package org.apache.spark.deploy.k8s.features
 
 import java.io.File
-import java.nio.charset.StandardCharsets
 
 import scala.jdk.CollectionConverters._
 import scala.util.control.NonFatal
@@ -236,7 +235,7 @@ private[spark] class KerberosConfDriverFeatureStep(kubernetesConf: KubernetesDri
             .endMetadata()
           .withImmutable(true)
           .addToData(
-            Map(file.getName() -> Files.asCharSource(file, StandardCharsets.UTF_8).read()).asJava)
+            Map(file.getName() -> java.nio.file.Files.readString(file.toPath)).asJava)
           .build()
       }
     } ++ {

resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/features/PodTemplateConfigMapStep.scala

@@ -17,9 +17,8 @@
 package org.apache.spark.deploy.k8s.features
 
 import java.io.File
-import java.nio.charset.StandardCharsets
+import java.nio.file.Files
 
-import com.google.common.io.Files
 import io.fabric8.kubernetes.api.model.{ConfigMapBuilder, ContainerBuilder, HasMetadata, PodBuilder}
 
 import org.apache.spark.deploy.SparkHadoopUtil
@@ -81,7 +80,7 @@ private[spark] class PodTemplateConfigMapStep(conf: KubernetesConf)
       val hadoopConf = SparkHadoopUtil.get.newConfiguration(conf.sparkConf)
       val uri = downloadFile(podTemplateFile, Utils.createTempDir(), conf.sparkConf, hadoopConf)
       val file = new java.net.URI(uri).getPath
-      val podTemplateString = Files.asCharSource(new File(file), StandardCharsets.UTF_8).read()
+      val podTemplateString = Files.readString(new File(file).toPath)
       Seq(new ConfigMapBuilder()
           .withNewMetadata()
             .withName(configmapName)

resource-managers/kubernetes/integration-tests/src/test/scala/org/apache/spark/deploy/k8s/integrationtest/KubernetesSuite.scala

@@ -17,13 +17,11 @@
 package org.apache.spark.deploy.k8s.integrationtest
 
 import java.io.File
-import java.nio.charset.StandardCharsets
-import java.nio.file.{Path, Paths}
+import java.nio.file.{Files, Path, Paths}
 import java.util.UUID
 
 import scala.jdk.CollectionConverters._
 
-import com.google.common.io.Files
 import io.fabric8.kubernetes.api.model.Pod
 import io.fabric8.kubernetes.client.{Watcher, WatcherException}
 import io.fabric8.kubernetes.client.KubernetesClientException
@@ -129,7 +127,7 @@ class KubernetesSuite extends SparkFunSuite
         val tagFile = new File(path)
         require(tagFile.isFile,
           s"No file found for image tag at ${tagFile.getAbsolutePath}.")
-        Files.asCharSource(tagFile, StandardCharsets.UTF_8).read().trim
+        Files.readString(tagFile.toPath).trim
       }
       .orElse(sys.props.get(CONFIG_KEY_IMAGE_TAG))
       .getOrElse {

resource-managers/yarn/src/test/scala/org/apache/spark/deploy/yarn/BaseYarnClusterSuite.scala

@@ -236,11 +236,11 @@ abstract class BaseYarnClusterSuite extends SparkFunSuite with Matchers {
     // an error message
     val output = new Object() {
       override def toString: String = outFile
-          .map(Files.asCharSource(_, StandardCharsets.UTF_8).read())
+          .map((f: File) => java.nio.file.Files.readString(f.toPath))
           .getOrElse("(stdout/stderr was not captured)")
     }
     assert(finalState === SparkAppHandle.State.FINISHED, output)
-    val resultString = Files.asCharSource(result, StandardCharsets.UTF_8).read()
+    val resultString = java.nio.file.Files.readString(result.toPath)
     assert(resultString === expected, output)
   }
 

resource-managers/yarn/src/test/scala/org/apache/spark/deploy/yarn/YarnClusterSuite.scala

@@ -377,7 +377,7 @@ class YarnClusterSuite extends BaseYarnClusterSuite {
       extraEnv = Map("SPARK_CONF_DIR" -> confDir.getAbsolutePath),
       extraConf = Map(CLIENT_INCLUDE_DRIVER_LOGS_LINK.key -> true.toString))
     checkResult(finalState, result)
-    val logOutput = Files.asCharSource(logOutFile, StandardCharsets.UTF_8).read()
+    val logOutput = java.nio.file.Files.readString(logOutFile.toPath)
     val logFilePattern = raw"""(?s).+\sDriver Logs \(<NAME>\): https?://.+/<NAME>(\?\S+)?\s.+"""
     logOutput should fullyMatch regex logFilePattern.replace("<NAME>", "stdout")
     logOutput should fullyMatch regex logFilePattern.replace("<NAME>", "stderr")

scalastyle-config.xml

@@ -297,6 +297,11 @@ This file is divided into 3 sections:
     <customMessage>Use Files.readString instead.</customMessage>
   </check>
 
+  <check customId="asCharSource" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
+    <parameters><parameter name="regex">\bFiles\.asCharSource\b</parameter></parameters>
+    <customMessage>Use Files.readString instead.</customMessage>
+  </check>
+
   <check customId="write" level="error" class="org.scalastyle.file.RegexChecker" enabled="true">
     <parameters><parameter name="regex">\bFileUtils\.write\b</parameter></parameters>
     <customMessage>Use Files.writeString instead.</customMessage>