diff --git a/libphonenumber/src/commonMain/kotlin/io/michaelrocks/libphonenumber/kotlin/Phonemetadata.kt b/libphonenumber/src/commonMain/kotlin/io/michaelrocks/libphonenumber/kotlin/Phonemetadata.kt
index 3a6be9e4..e40e5074 100644
--- a/libphonenumber/src/commonMain/kotlin/io/michaelrocks/libphonenumber/kotlin/Phonemetadata.kt
+++ b/libphonenumber/src/commonMain/kotlin/io/michaelrocks/libphonenumber/kotlin/Phonemetadata.kt
@@ -335,41 +335,41 @@ class Phonemetadata private constructor() {
             return nationalNumberPattern == other.nationalNumberPattern && possibleLength_ == other.possibleLength_ && possibleLengthLocalOnly_ == other.possibleLengthLocalOnly_ && exampleNumber == other.exampleNumber
         }
 
-        override fun writeExternal(objectOutput: ObjectOutput) {
-            objectOutput.writeBoolean(hasNationalNumberPattern)
+        override fun writeExternal(out: ObjectOutput) {
+            out.writeBoolean(hasNationalNumberPattern)
             if (hasNationalNumberPattern) {
-                objectOutput.writeUTF(nationalNumberPattern)
+                out.writeUTF(nationalNumberPattern)
             }
             val possibleLengthSize = possibleLengthCount
-            objectOutput.writeInt(possibleLengthSize)
+            out.writeInt(possibleLengthSize)
             for (i in 0 until possibleLengthSize) {
-                objectOutput.writeInt(possibleLength_[i])
+                out.writeInt(possibleLength_[i])
             }
             val possibleLengthLocalOnlySize = possibleLengthLocalOnlyCount
-            objectOutput.writeInt(possibleLengthLocalOnlySize)
+            out.writeInt(possibleLengthLocalOnlySize)
             for (i in 0 until possibleLengthLocalOnlySize) {
-                objectOutput.writeInt(possibleLengthLocalOnly_[i])
+                out.writeInt(possibleLengthLocalOnly_[i])
             }
-            objectOutput.writeBoolean(hasExampleNumber)
+            out.writeBoolean(hasExampleNumber)
             if (hasExampleNumber) {
-                objectOutput.writeUTF(exampleNumber)
+                out.writeUTF(exampleNumber)
             }
         }
 
-        override fun readExternal(objectInput: ObjectInput) {
-            if (objectInput.readBoolean()) {
-                setNationalNumberPattern(objectInput.readUTF())
+        override fun readExternal(input: ObjectInput) {
+            if (input.readBoolean()) {
+                setNationalNumberPattern(input.readUTF())
             }
-            val possibleLengthSize = objectInput.readInt()
+            val possibleLengthSize = input.readInt()
             for (i in 0 until possibleLengthSize) {
-                possibleLength_.add(objectInput.readInt())
+                possibleLength_.add(input.readInt())
             }
-            val possibleLengthLocalOnlySize = objectInput.readInt()
+            val possibleLengthLocalOnlySize = input.readInt()
             for (i in 0 until possibleLengthLocalOnlySize) {
-                possibleLengthLocalOnly_.add(objectInput.readInt())
+                possibleLengthLocalOnly_.add(input.readInt())
             }
-            if (objectInput.readBoolean()) {
-                setExampleNumber(objectInput.readUTF())
+            if (input.readBoolean()) {
+                setExampleNumber(input.readUTF())
             }
         }
 
diff --git a/libphonenumber/src/commonMain/kotlin/io/michaelrocks/libphonenumber/kotlin/internal/RegexBasedMatcher.kt b/libphonenumber/src/commonMain/kotlin/io/michaelrocks/libphonenumber/kotlin/internal/RegexBasedMatcher.kt
index 2de96b21..c709d840 100644
--- a/libphonenumber/src/commonMain/kotlin/io/michaelrocks/libphonenumber/kotlin/internal/RegexBasedMatcher.kt
+++ b/libphonenumber/src/commonMain/kotlin/io/michaelrocks/libphonenumber/kotlin/internal/RegexBasedMatcher.kt
@@ -33,7 +33,7 @@ class RegexBasedMatcher private constructor() : MatcherApi {
         val nationalNumberPattern = numberDesc.nationalNumberPattern
         // We don't want to consider it a prefix match when matching non-empty input against an empty
         // pattern.
-        return if (nationalNumberPattern.length == 0) {
+        return if (nationalNumberPattern.isEmpty()) {
             false
         } else match(number, regexCache.getRegexForPattern(nationalNumberPattern), allowPrefixMatch);
     }
diff --git a/libphonenumber/src/commonTest/kotlin/io/michaelrocks/libphonenumber/kotlin/internal/MatcherTest.kt b/libphonenumber/src/commonTest/kotlin/io/michaelrocks/libphonenumber/kotlin/internal/MatcherTest.kt
index c1df8baf..83b9c766 100644
--- a/libphonenumber/src/commonTest/kotlin/io/michaelrocks/libphonenumber/kotlin/internal/MatcherTest.kt
+++ b/libphonenumber/src/commonTest/kotlin/io/michaelrocks/libphonenumber/kotlin/internal/MatcherTest.kt
@@ -60,7 +60,7 @@ class MatcherTest {
     // set.
     private fun createDesc(nationalNumberPattern: String): PhoneNumberDesc {
         val desc = newBuilder()
-        if (nationalNumberPattern.length > 0) {
+        if (nationalNumberPattern.isNotEmpty()) {
             desc.setNationalNumberPattern(nationalNumberPattern)
         }
         return desc.build()