src/java.base/share/classes/java/lang/StringUTF16.java

@@ -34,10 +34,11 @@
 import static java.lang.String.UTF16;
 import static java.lang.String.LATIN1;
 import static java.lang.String.checkIndex;
 import static java.lang.String.checkOffset;
 import static java.lang.String.checkBoundsOffCount;
+import static java.lang.String.checkBoundsBeginEnd;
 
 final class StringUTF16 {
 
     public static byte[] newBytesFor(int len) {
         if (len < 0) {

@@ -411,10 +412,11 @@
             }
         }
         return -1;
     }
 
+    // srcCoder == UTF16 && tgtCoder == UTF16
     public static int lastIndexOf(byte[] src, int srcCount,
                                   byte[] tgt, int tgtCount, int fromIndex) {
         int min = tgtCount - 1;
         int i = min + fromIndex;
         int strLastIndex = tgtCount - 1;

@@ -930,16 +932,16 @@
         checkIndex(index, val.length >> 1);
         putChar(val, index, c);
     }
 
     public static void putCharsSB(byte[] val, int index, char[] ca, int off, int end) {
-        checkOffset(index + end - off, val.length >> 1);
+        checkBoundsOffCount(index, index + end - off, val.length >> 1);
         putChars(val, index, ca, off, end);
     }
 
     public static void putCharsSB(byte[] val, int index, CharSequence s, int off, int end) {
-        checkOffset(index + end - off, val.length >> 1);
+        checkBoundsOffCount(index, end - off, val.length >> 1);
         for (int i = off; i < end; i++) {
             putChar(val, index++, s.charAt(i));
         }
     }
 

@@ -952,11 +954,11 @@
         checkOffset(index, val.length >> 1);
         return codePointBefore(val, index);
     }
 
     public static int codePointCountSB(byte[] val, int beginIndex, int endIndex) {
-        checkOffset(endIndex, val.length >> 1);
+        checkBoundsBeginEnd(beginIndex, endIndex, val.length >> 1);
         return codePointCount(val, beginIndex, endIndex);
     }
 
     ////////////////////////////////////////////////////////////////