diff --git a/mockwebserver/src/main/java/okhttp3/mockwebserver/MockWebServer.kt b/mockwebserver/src/main/java/okhttp3/mockwebserver/MockWebServer.kt
index 8499e1993..1029222ee 100644
--- a/mockwebserver/src/main/java/okhttp3/mockwebserver/MockWebServer.kt
+++ b/mockwebserver/src/main/java/okhttp3/mockwebserver/MockWebServer.kt
@@ -705,7 +705,7 @@ class MockWebServer : ExternalResource(), Closeable {
         .url("$scheme://$authority/")
         .headers(request.headers)
         .build()
-    val statusParts = response.getStatus().split(" ".toRegex(), 3)
+    val statusParts = response.getStatus().split(' ', limit = 3)
     val fancyResponse = Response.Builder()
         .code(Integer.parseInt(statusParts[1]))
         .message(statusParts[2])
@@ -970,7 +970,7 @@ class MockWebServer : ExternalResource(), Closeable {
         return
       }
       val http2Headers = ArrayList<Header>()
-      val statusParts = response.getStatus().split(" ".toRegex(), 3).toTypedArray()
+      val statusParts = response.getStatus().split(' ', limit = 3)
       if (statusParts.size < 2) {
         throw AssertionError("Unexpected status: ${response.getStatus()}")
       }
diff --git a/okcurl/src/main/java/okhttp3/curl/Main.kt b/okcurl/src/main/java/okhttp3/curl/Main.kt
index 3c0f3fd54..d93150581 100644
--- a/okcurl/src/main/java/okhttp3/curl/Main.kt
+++ b/okcurl/src/main/java/okhttp3/curl/Main.kt
@@ -191,7 +191,7 @@ class Main : Runnable {
     }
 
     for (header in headers.orEmpty()) {
-      val parts = header.split(":".toRegex(), 2).toTypedArray()
+      val parts = header.split(':', limit = 2)
       request.header(parts[0], parts[1])
     }
     referer?.let {
@@ -205,7 +205,7 @@ class Main : Runnable {
   private fun mediaType(): MediaType? {
     val mimeType = headers?.let {
       for (header in it) {
-        val parts = header.split(":".toRegex()).toTypedArray()
+        val parts = header.split(':')
         if ("Content-Type".equals(parts[0], ignoreCase = true)) {
           it.remove(header)
           return@let parts[1].trim()
diff --git a/okhttp-dnsoverhttps/src/main/java/okhttp3/dnsoverhttps/DnsRecordCodec.kt b/okhttp-dnsoverhttps/src/main/java/okhttp3/dnsoverhttps/DnsRecordCodec.kt
index 0551d39f6..012ba4202 100644
--- a/okhttp-dnsoverhttps/src/main/java/okhttp3/dnsoverhttps/DnsRecordCodec.kt
+++ b/okhttp-dnsoverhttps/src/main/java/okhttp3/dnsoverhttps/DnsRecordCodec.kt
@@ -45,7 +45,7 @@ object DnsRecordCodec {
     writeShort(0) // additional
 
     val nameBuf = Buffer()
-    val labels = host.split('.').dropLastWhile { it.isEmpty() }.toTypedArray()
+    val labels = host.split('.').dropLastWhile { it.isEmpty() }
     for (label in labels) {
       val utf8ByteCount = label.utf8Size()
       if (utf8ByteCount != label.length.toLong()) {
diff --git a/okhttp/src/main/java/okhttp3/internal/cache/DiskLruCache.kt b/okhttp/src/main/java/okhttp3/internal/cache/DiskLruCache.kt
index c261191a9..66b1ea70e 100644
--- a/okhttp/src/main/java/okhttp3/internal/cache/DiskLruCache.kt
+++ b/okhttp/src/main/java/okhttp3/internal/cache/DiskLruCache.kt
@@ -39,7 +39,6 @@ import java.util.concurrent.Executor
 import java.util.concurrent.LinkedBlockingQueue
 import java.util.concurrent.ThreadPoolExecutor
 import java.util.concurrent.TimeUnit
-import java.util.regex.Pattern
 
 /**
  * A cache that uses a bounded amount of space on a filesystem. Each cache entry has a string key
@@ -317,8 +316,7 @@ class DiskLruCache internal constructor(
     when {
       secondSpace != -1 && firstSpace == CLEAN.length && line.startsWith(CLEAN) -> {
         val parts = line.substring(secondSpace + 1)
-            .split(" ".toRegex())
-            .toTypedArray()
+            .split(' ')
         entry.readable = true
         entry.currentEditor = null
         entry.setLengths(parts)
@@ -670,8 +668,7 @@ class DiskLruCache internal constructor(
   }
 
   private fun validateKey(key: String) {
-    val matcher = LEGAL_KEY_PATTERN.matcher(key)
-    require(matcher.matches()) { "keys must match regex [a-z0-9_-]{1,120}: \"$key\"" }
+    require(LEGAL_KEY_PATTERN.matches(key)) { "keys must match regex [a-z0-9_-]{1,120}: \"$key\"" }
   }
 
   /**
@@ -905,7 +902,7 @@ class DiskLruCache internal constructor(
 
     /** Set lengths using decimal numbers like "10123".  */
     @Throws(IOException::class)
-    internal fun setLengths(strings: Array<String>) {
+    internal fun setLengths(strings: List<String>) {
       if (strings.size != valueCount) {
         throw invalidLengths(strings)
       }
@@ -928,8 +925,8 @@ class DiskLruCache internal constructor(
     }
 
     @Throws(IOException::class)
-    private fun invalidLengths(strings: Array<String>): IOException {
-      throw IOException("unexpected journal line: ${strings.contentToString()}")
+    private fun invalidLengths(strings: List<String>): IOException {
+      throw IOException("unexpected journal line: $strings")
     }
 
     /**
@@ -970,7 +967,7 @@ class DiskLruCache internal constructor(
     @JvmField val MAGIC = "libcore.io.DiskLruCache"
     @JvmField val VERSION_1 = "1"
     @JvmField val ANY_SEQUENCE_NUMBER: Long = -1
-    @JvmField val LEGAL_KEY_PATTERN = Pattern.compile("[a-z0-9_-]{1,120}")
+    @JvmField val LEGAL_KEY_PATTERN = "[a-z0-9_-]{1,120}".toRegex()
     @JvmField val CLEAN = "CLEAN"
     @JvmField val DIRTY = "DIRTY"
     @JvmField val REMOVE = "REMOVE"