diff --git a/src/java.base/share/classes/java/lang/StringConcatHelper.java b/src/java.base/share/classes/java/lang/StringConcatHelper.java
index eddfc7e6496..28b9b754bbd 100644
--- a/src/java.base/share/classes/java/lang/StringConcatHelper.java
+++ b/src/java.base/share/classes/java/lang/StringConcatHelper.java
@@ -138,7 +138,6 @@ final class StringConcatHelper {
     @PreviewFeature(feature=PreviewFeature.Feature.STRING_TEMPLATES)
     static long mix(long lengthCoder, FormatConcatItem value) {
         lengthCoder = value.mix(lengthCoder);
-
         return checkOverflow(lengthCoder);
     }
 
@@ -152,7 +151,7 @@ final class StringConcatHelper {
      * @param value      boolean value to encode
      * @return           updated index (coder value retained)
      */
-    private static long prepend(long indexCoder, byte[] buf, boolean value) {
+    static long prepend(long indexCoder, byte[] buf, boolean value) {
         int index = (int)indexCoder;
         if (indexCoder < UTF16) {
             if (value) {
@@ -198,7 +197,7 @@ final class StringConcatHelper {
      */
     static long prepend(long indexCoder, byte[] buf, boolean value, String prefix) {
         indexCoder = prepend(indexCoder, buf, value);
-        if (prefix != null) indexCoder = prepend(indexCoder, buf, prefix);
+        indexCoder = prepend(indexCoder, buf, prefix);
         return indexCoder;
     }
 
@@ -212,7 +211,7 @@ final class StringConcatHelper {
      * @param value      char value to encode
      * @return           updated index (coder value retained)
      */
-    private static long prepend(long indexCoder, byte[] buf, char value) {
+    static long prepend(long indexCoder, byte[] buf, char value) {
         if (indexCoder < UTF16) {
             buf[(int)(--indexCoder)] = (byte) (value & 0xFF);
         } else {
@@ -234,7 +233,7 @@ final class StringConcatHelper {
      */
     static long prepend(long indexCoder, byte[] buf, char value, String prefix) {
         indexCoder = prepend(indexCoder, buf, value);
-        if (prefix != null) indexCoder = prepend(indexCoder, buf, prefix);
+        indexCoder = prepend(indexCoder, buf, prefix);
         return indexCoder;
     }
 
@@ -248,7 +247,7 @@ final class StringConcatHelper {
      * @param value      integer value to encode
      * @return           updated index (coder value retained)
      */
-    private static long prepend(long indexCoder, byte[] buf, int value) {
+    static long prepend(long indexCoder, byte[] buf, int value) {
         if (indexCoder < UTF16) {
             return StringLatin1.getChars(value, (int)indexCoder, buf);
         } else {
@@ -269,7 +268,7 @@ final class StringConcatHelper {
      */
     static long prepend(long indexCoder, byte[] buf, int value, String prefix) {
         indexCoder = prepend(indexCoder, buf, value);
-        if (prefix != null) indexCoder = prepend(indexCoder, buf, prefix);
+        indexCoder = prepend(indexCoder, buf, prefix);
         return indexCoder;
     }
 
@@ -283,7 +282,7 @@ final class StringConcatHelper {
      * @param value      long value to encode
      * @return           updated index (coder value retained)
      */
-    private static long prepend(long indexCoder, byte[] buf, long value) {
+    static long prepend(long indexCoder, byte[] buf, long value) {
         if (indexCoder < UTF16) {
             return StringLatin1.getChars(value, (int)indexCoder, buf);
         } else {
@@ -304,7 +303,7 @@ final class StringConcatHelper {
      */
     static long prepend(long indexCoder, byte[] buf, long value, String prefix) {
         indexCoder = prepend(indexCoder, buf, value);
-        if (prefix != null) indexCoder = prepend(indexCoder, buf, prefix);
+        indexCoder = prepend(indexCoder, buf, prefix);
         return indexCoder;
     }
 
@@ -318,7 +317,7 @@ final class StringConcatHelper {
      * @param value      String value to encode
      * @return           updated index (coder value retained)
      */
-    private static long prepend(long indexCoder, byte[] buf, String value) {
+    static long prepend(long indexCoder, byte[] buf, String value) {
         indexCoder -= value.length();
         if (indexCoder < UTF16) {
             value.getBytes(buf, (int)indexCoder, String.LATIN1);
@@ -341,7 +340,7 @@ final class StringConcatHelper {
      */
     static long prepend(long indexCoder, byte[] buf, String value, String prefix) {
         indexCoder = prepend(indexCoder, buf, value);
-        if (prefix != null) indexCoder = prepend(indexCoder, buf, prefix);
+        indexCoder = prepend(indexCoder, buf, prefix);
         return indexCoder;
     }
 
@@ -357,8 +356,7 @@ final class StringConcatHelper {
      * @since 21
      */
     @PreviewFeature(feature=PreviewFeature.Feature.STRING_TEMPLATES)
-    private static long prepend(long indexCoder, byte[] buf,
-                                FormatConcatItem value) {
+    static long prepend(long indexCoder, byte[] buf, FormatConcatItem value) {
         try {
             return value.prepend(indexCoder, buf);
         } catch (Error ex) {
@@ -384,7 +382,7 @@ final class StringConcatHelper {
     static long prepend(long indexCoder, byte[] buf,
                         FormatConcatItem value, String prefix) {
         indexCoder = prepend(indexCoder, buf, value);
-        if (prefix != null) indexCoder = prepend(indexCoder, buf, prefix);
+        indexCoder = prepend(indexCoder, buf, prefix);
         return indexCoder;
     }
 
@@ -586,7 +584,8 @@ final class StringConcatHelper {
 
     static MethodHandle lookupStatic(String name, MethodType methodType) {
         try {
-            return MethodHandles.lookup().findStatic(StringConcatHelper.class, name, methodType);
+            return MethodHandles.lookup()
+                    .findStatic(StringConcatHelper.class, name, methodType);
         } catch (NoSuchMethodException|IllegalAccessException e) {
             throw new AssertionError(e);
         }
diff --git a/src/java.base/share/classes/java/lang/invoke/StringConcatFactory.java b/src/java.base/share/classes/java/lang/invoke/StringConcatFactory.java
index 6fa79baccb9..cc0abfef97c 100644
--- a/src/java.base/share/classes/java/lang/invoke/StringConcatFactory.java
+++ b/src/java.base/share/classes/java/lang/invoke/StringConcatFactory.java
@@ -700,19 +700,12 @@ public final class StringConcatFactory {
     // Simple prependers, single argument. May be used directly or as a
     // building block for complex prepender combinators.
     private static MethodHandle prepender(String prefix, Class<?> cl) {
-        MethodHandle prepend;
-        int idx = classIndex(cl);
-        if (prefix == null) {
-            prepend = NULL_PREPENDERS[idx];
-            if (prepend == null) {
-                NULL_PREPENDERS[idx] = prepend = MethodHandles.insertArguments(
-                                prepender(cl), 3, (String)null);
-            }
+        if (prefix == null || prefix.isEmpty()) {
+            return noPrefixPrepender(cl);
         } else {
-            prepend = MethodHandles.insertArguments(
+            return MethodHandles.insertArguments(
                     prepender(cl), 3, prefix);
         }
-        return prepend;
     }
 
     private static MethodHandle prepender(Class<?> cl) {
@@ -729,6 +722,20 @@ public final class StringConcatFactory {
         return prepend;
     }
 
+    private static MethodHandle noPrefixPrepender(Class<?> cl) {
+        int idx = classIndex(cl);
+        MethodHandle prepend = NO_PREFIX_PREPENDERS[idx];
+        if (prepend == null) {
+            if (idx == STRING_CONCAT_ITEM) {
+                cl = FormatConcatItem.class;
+            }
+            NO_PREFIX_PREPENDERS[idx] = prepend = JLA.stringConcatHelper("prepend",
+                    methodType(long.class, long.class, byte[].class,
+                            Wrapper.asPrimitiveType(cl))).rebind();
+        }
+        return prepend;
+    }
+
     private static final int INT_IDX = 0,
             CHAR_IDX = 1,
             LONG_IDX = 2,
@@ -995,7 +1002,7 @@ public final class StringConcatFactory {
         }
     }
 
-    private static final @Stable MethodHandle[] NULL_PREPENDERS = new MethodHandle[TYPE_COUNT];
+    private static final @Stable MethodHandle[] NO_PREFIX_PREPENDERS = new MethodHandle[TYPE_COUNT];
     private static final @Stable MethodHandle[] PREPENDERS      = new MethodHandle[TYPE_COUNT];
     private static final @Stable MethodHandle[] MIXERS          = new MethodHandle[TYPE_COUNT];
     private static final long INITIAL_CODER = JLA.stringConcatInitialCoder();
@@ -1117,7 +1124,7 @@ public final class StringConcatFactory {
 
             Class<?> ttype = ttypes[pos];
             // (long,byte[],ttype) -> long
-            MethodHandle prepender = prepender(fragment.isEmpty() ? null : fragment, ttype);
+            MethodHandle prepender = prepender(fragment, ttype);
             // (byte[],long,ttypes...) -> String (unchanged)
             mh = MethodHandles.filterArgumentsWithCombiner(mh, 1, prepender,1, 0, 2 + pos);
 
diff --git a/src/java.base/share/classes/java/util/FormatItem.java b/src/java.base/share/classes/java/util/FormatItem.java
index 728d4aee3b7..9ac700ffa4f 100644
--- a/src/java.base/share/classes/java/util/FormatItem.java
+++ b/src/java.base/share/classes/java/util/FormatItem.java
@@ -61,7 +61,7 @@ class FormatItem {
     private static final MethodHandle STRING_PREPEND =
             JLA.stringConcatHelper("prepend",
                     MethodType.methodType(long.class, long.class, byte[].class,
-                            String.class, String.class));
+                            String.class));
 
     private static final MethodHandle SELECT_GETCHAR_MH =
             JLA.stringConcatHelper("selectGetChar",
@@ -87,8 +87,7 @@ class FormatItem {
 
     private static long stringPrepend(long lengthCoder, byte[] buffer,
                                             String value) throws Throwable {
-        return (long)STRING_PREPEND.invokeExact(lengthCoder, buffer, value,
-                (String)null);
+        return (long)STRING_PREPEND.invokeExact(lengthCoder, buffer, value);
     }
 
     private static MethodHandle selectGetChar(long indexCoder) throws Throwable {