diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index c52b3be..0d24f8f 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: ['17']
+        java: ['22']
     steps:
       - uses: actions/checkout@v1
       - name: Setup test JDK ${{ matrix.java }}
@@ -15,10 +15,10 @@ jobs:
         with:
           java-version: ${{ matrix.java }}
       - run: echo "test_java_home=$JAVA_HOME" >> $GITHUB_ENV
-      - name: Setup build JDK 17
+      - name: Setup build JDK 22
         uses: actions/setup-java@v1
         with:
-          java-version: 17
+          java-version: 22
       - name: Maven Test
         run: mvn install -V -B -Dtest_java_home=${{ env.test_java_home }}
 
diff --git a/pom.xml b/pom.xml
index 3073d35..445220e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -96,7 +96,8 @@
                 <artifactId>maven-compiler-plugin</artifactId>
                 <version>3.8.1</version>
                 <configuration>
-                    <release>17</release>
+                    <source>22</source>
+                    <release>22</release>
                 </configuration>
             </plugin>
         </plugins>
diff --git a/src/main/java/org/weakref/int128/Int128.java b/src/main/java/org/weakref/int128/Int128.java
index 6c21c2c..67d8b90 100644
--- a/src/main/java/org/weakref/int128/Int128.java
+++ b/src/main/java/org/weakref/int128/Int128.java
@@ -19,10 +19,10 @@
 import java.nio.ByteOrder;
 import java.util.concurrent.ThreadLocalRandom;
 
+import static java.lang.Math.unsignedMultiplyHigh;
 import static org.weakref.int128.MoreMath.ifNegative;
 import static org.weakref.int128.MoreMath.unsignedBorrow;
 import static org.weakref.int128.MoreMath.unsignedCarry;
-import static org.weakref.int128.MoreMath.unsignedMultiplyHigh;
 
 public record Int128(long high, long low)
         implements Comparable<Int128>
diff --git a/src/main/java/org/weakref/int128/Int128Math.java b/src/main/java/org/weakref/int128/Int128Math.java
index ec18bc4..ffe9d54 100644
--- a/src/main/java/org/weakref/int128/Int128Math.java
+++ b/src/main/java/org/weakref/int128/Int128Math.java
@@ -13,6 +13,8 @@
  */
 package org.weakref.int128;
 
+import static java.lang.Math.unsignedMultiplyHigh;
+
 public final class Int128Math
 {
     private Int128Math() {}
@@ -138,7 +140,7 @@ public static long subtractLowExact(long aHigh, long aLow, long bHigh, long bLow
 
     public static long multiplyHigh(long aHigh, long aLow, long bHigh, long bLow)
     {
-        return MoreMath.unsignedMultiplyHigh(aLow, bLow) + aLow * bHigh + aHigh * bLow;
+        return unsignedMultiplyHigh(aLow, bLow) + aLow * bHigh + aHigh * bLow;
     }
 
     public static long multiplyLow(long aHigh, long aLow, long bHigh, long bLow)
diff --git a/src/main/java/org/weakref/int128/MoreMath.java b/src/main/java/org/weakref/int128/MoreMath.java
index d7f39dc..fa1f026 100644
--- a/src/main/java/org/weakref/int128/MoreMath.java
+++ b/src/main/java/org/weakref/int128/MoreMath.java
@@ -53,11 +53,4 @@ public static long ifNegative(long test, long value)
     {
         return value & (test >> 63);
     }
-
-    // TODO: replace with JDK 18's Math.unsignedMultiplyHigh
-    public static long unsignedMultiplyHigh(long x, long y)
-    {
-        // HD 8-3: High-Order Product Signed from/to Unsigned
-        return Math.multiplyHigh(x, y) + ifNegative(x, y) + ifNegative(y, x);
-    }
 }