MINOR: A few cleanups and compiler warning fixes (#6986)

Reviewers: Jason Gustafson <jason@confluent.io>

clients/src/main/java/org/apache/kafka/common/utils/Utils.java

@@ -602,15 +602,6 @@ public final class Utils {
         return sw.toString();
     }
 
-    /**
-     * Print an error message and shutdown the JVM
-     * @param message The error message
-     */
-    public static void croak(String message) {
-        System.err.println(message);
-        Exit.exit(1);
-    }
-
     /**
      * Read a buffer into a Byte array for the given offset and length
      */
@@ -869,7 +860,6 @@ public final class Utils {
         }
     }
 
-
     /**
      * A cheap way to deterministically convert a number to a positive value. When the input is
      * positive, the original value is returned. When the input number is negative, the returned

clients/src/test/java/org/apache/kafka/common/record/ByteBufferLogInputStreamTest.java

@@ -19,7 +19,6 @@ package org.apache.kafka.common.record;
 import org.apache.kafka.common.errors.CorruptRecordException;
 import org.junit.Test;
 
-import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.Iterator;
 
@@ -56,7 +55,7 @@ public class ByteBufferLogInputStreamTest {
     }
 
     @Test(expected = CorruptRecordException.class)
-    public void iteratorRaisesOnTooSmallRecords() throws IOException {
+    public void iteratorRaisesOnTooSmallRecords() {
         ByteBuffer buffer = ByteBuffer.allocate(1024);
         MemoryRecordsBuilder builder = MemoryRecords.builder(buffer, CompressionType.NONE, TimestampType.CREATE_TIME, 0L);
         builder.append(15L, "a".getBytes(), "1".getBytes());
@@ -79,7 +78,7 @@ public class ByteBufferLogInputStreamTest {
     }
 
     @Test(expected = CorruptRecordException.class)
-    public void iteratorRaisesOnInvalidMagic() throws IOException {
+    public void iteratorRaisesOnInvalidMagic() {
         ByteBuffer buffer = ByteBuffer.allocate(1024);
         MemoryRecordsBuilder builder = MemoryRecords.builder(buffer, CompressionType.NONE, TimestampType.CREATE_TIME, 0L);
         builder.append(15L, "a".getBytes(), "1".getBytes());
@@ -102,7 +101,7 @@ public class ByteBufferLogInputStreamTest {
     }
 
     @Test(expected = CorruptRecordException.class)
-    public void iteratorRaisesOnTooLargeRecords() throws IOException {
+    public void iteratorRaisesOnTooLargeRecords() {
         ByteBuffer buffer = ByteBuffer.allocate(1024);
         MemoryRecordsBuilder builder = MemoryRecords.builder(buffer, CompressionType.NONE, TimestampType.CREATE_TIME, 0L);
         builder.append(15L, "a".getBytes(), "1".getBytes());

core/src/test/scala/unit/kafka/log/LogValidatorTest.scala

@@ -1178,7 +1178,7 @@ class LogValidatorTest {
   }
 
   private def createTwoBatchedRecords(magicValue: Byte,
-                                      timestamp: Long = RecordBatch.NO_TIMESTAMP,
+                                      timestamp: Long,
                                       codec: CompressionType): MemoryRecords = {
     val buf = ByteBuffer.allocate(2048)
     var builder = MemoryRecords.builder(buf, magicValue, codec, TimestampType.CREATE_TIME, 0L)
@@ -1193,16 +1193,6 @@ class LogValidatorTest {
     MemoryRecords.readableRecords(buf.slice())
   }
 
-  private def createDiscontinuousOffsetRecords(magicValue: Byte,
-                                               codec: CompressionType): MemoryRecords = {
-    val buf = ByteBuffer.allocate(512)
-    val builder = MemoryRecords.builder(buf, magicValue, codec, TimestampType.CREATE_TIME, 0L)
-    builder.appendWithOffset(0, RecordBatch.NO_TIMESTAMP, null, "hello".getBytes)
-    builder.appendWithOffset(2, RecordBatch.NO_TIMESTAMP, null, "there".getBytes)
-    builder.appendWithOffset(3, RecordBatch.NO_TIMESTAMP, null, "beautiful".getBytes)
-    builder.build()
-  }
-
   /* check that offsets are assigned consecutively from the given base offset */
   def checkOffsets(records: MemoryRecords, baseOffset: Long) {
     assertTrue("Message set should not be empty", records.records.asScala.nonEmpty)

core/src/test/scala/unit/kafka/log/TransactionIndexTest.scala

@@ -22,7 +22,7 @@ import kafka.utils.TestUtils
 import org.apache.kafka.common.requests.FetchResponse.AbortedTransaction
 import org.junit.Assert._
 import org.junit.{After, Before, Test}
-import org.scalatest.junit.JUnitSuite
+import org.scalatestplus.junit.JUnitSuite
 
 class TransactionIndexTest extends JUnitSuite {
   var file: File = _

core/src/test/scala/unit/kafka/security/auth/AclTest.scala

@@ -21,7 +21,7 @@ import java.nio.charset.StandardCharsets.UTF_8
 import kafka.utils.Json
 import org.apache.kafka.common.security.auth.KafkaPrincipal
 import org.junit.{Assert, Test}
-import org.scalatest.junit.JUnitSuite
+import org.scalatestplus.junit.JUnitSuite
 import scala.collection.JavaConverters._
 
 class AclTest extends JUnitSuite {