diff --git a/staticlibs/framework/com/android/net/module/util/HexDump.java b/staticlibs/framework/com/android/net/module/util/HexDump.java
index a22c258..409f611 100644
--- a/staticlibs/framework/com/android/net/module/util/HexDump.java
+++ b/staticlibs/framework/com/android/net/module/util/HexDump.java
@@ -202,7 +202,7 @@
         if (c >= 'A' && c <= 'F') return (c - 'A' + 10);
         if (c >= 'a' && c <= 'f') return (c - 'a' + 10);
 
-        throw new RuntimeException("Invalid hex char '" + c + "'");
+        throw new IllegalArgumentException("Invalid hex char '" + c + "'");
     }
 
     /**
diff --git a/staticlibs/tests/unit/src/com/android/net/module/util/HexDumpTest.java b/staticlibs/tests/unit/src/com/android/net/module/util/HexDumpTest.java
index 5a15585..f81978a 100644
--- a/staticlibs/tests/unit/src/com/android/net/module/util/HexDumpTest.java
+++ b/staticlibs/tests/unit/src/com/android/net/module/util/HexDumpTest.java
@@ -18,6 +18,7 @@
 
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThrows;
 
 import androidx.test.filters.SmallTest;
 import androidx.test.runner.AndroidJUnit4;
@@ -50,6 +51,11 @@
     }
 
     @Test
+    public void testInvalidHexStringToByteArray() {
+        assertThrows(IllegalArgumentException.class, () -> HexDump.hexStringToByteArray("abxX"));
+    }
+
+    @Test
     public void testIntegerToByteArray() {
         assertArrayEquals(new byte[]{(byte) 0xff, (byte) 0x00, (byte) 0x00, (byte) 0x04},
                 HexDump.toByteArray((int) 0xff000004));