diff --git a/core/java/android/os/FileUtils.java b/core/java/android/os/FileUtils.java
index d5c3de1460154..b478a37984e03 100644
--- a/core/java/android/os/FileUtils.java
+++ b/core/java/android/os/FileUtils.java
@@ -84,7 +84,6 @@ import java.security.NoSuchAlgorithmException;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Comparator;
-import java.util.List;
 import java.util.Objects;
 import java.util.concurrent.Executor;
 import java.util.concurrent.TimeUnit;
@@ -1314,31 +1313,31 @@ public final class FileUtils {
     private static long toBytes(long value, String unit) {
         unit = unit.toUpperCase();
 
-        if (List.of("B").contains(unit)) {
+        if ("B".equals(unit)) {
             return value;
         }
 
-        if (List.of("K", "KB").contains(unit)) {
+        if ("K".equals(unit) || "KB".equals(unit)) {
             return DataUnit.KILOBYTES.toBytes(value);
         }
 
-        if (List.of("M", "MB").contains(unit)) {
+        if ("M".equals(unit) || "MB".equals(unit)) {
             return DataUnit.MEGABYTES.toBytes(value);
         }
 
-        if (List.of("G", "GB").contains(unit)) {
+        if ("G".equals(unit) || "GB".equals(unit)) {
             return DataUnit.GIGABYTES.toBytes(value);
         }
 
-        if (List.of("KI", "KIB").contains(unit)) {
+        if ("KI".equals(unit) || "KIB".equals(unit)) {
             return DataUnit.KIBIBYTES.toBytes(value);
         }
 
-        if (List.of("MI", "MIB").contains(unit)) {
+        if ("MI".equals(unit) || "MIB".equals(unit)) {
             return DataUnit.MEBIBYTES.toBytes(value);
         }
 
-        if (List.of("GI", "GIB").contains(unit)) {
+        if ("GI".equals(unit) || "GIB".equals(unit)) {
             return DataUnit.GIBIBYTES.toBytes(value);
         }
 
@@ -1370,7 +1369,7 @@ public final class FileUtils {
                 sign = -1;
             }
 
-            fmtSize = fmtSize.replace(first + "", "");
+            fmtSize = fmtSize.substring(1);
         }
 
         int index = 0;