8340132: Remove internal CpException for reading malformed utf8

Reviewed-by: asotona

Author: liach

src/java.base/share/classes/jdk/internal/classfile/impl/AbstractPoolEntry.java

@@ -24,6 +24,7 @@
  */
 package jdk.internal.classfile.impl;
 
+import java.lang.classfile.constantpool.ConstantPoolException;
 import java.lang.constant.*;
 import java.lang.invoke.TypeDescriptor;
 import java.nio.charset.StandardCharsets;
@@ -258,11 +259,11 @@ private void inflate() {
                             // 110x xxxx  10xx xxxx
                             px += 2;
                             if (px > utfend) {
-                                throw new CpException("malformed input: partial character at end");
+                                throw malformedInput(utfend);
                             }
                             int char2 = rawBytes[px - 1];
                             if ((char2 & 0xC0) != 0x80) {
-                                throw new CpException("malformed input around byte " + px);
+                                throw malformedInput(px);
                             }
                             char v = (char) (((c & 0x1F) << 6) | (char2 & 0x3F));
                             chararr[chararr_count++] = v;
@@ -273,12 +274,12 @@ private void inflate() {
                             // 1110 xxxx  10xx xxxx  10xx xxxx
                             px += 3;
                             if (px > utfend) {
-                                throw new CpException("malformed input: partial character at end");
+                                throw malformedInput(utfend);
                             }
                             int char2 = rawBytes[px - 2];
                             int char3 = rawBytes[px - 1];
                             if (((char2 & 0xC0) != 0x80) || ((char3 & 0xC0) != 0x80)) {
-                                throw new CpException("malformed input around byte " + (px - 1));
+                                throw malformedInput(px - 1);
                             }
                             char v = (char) (((c & 0x0F) << 12) | ((char2 & 0x3F) << 6) | (char3 & 0x3F));
                             chararr[chararr_count++] = v;
@@ -287,15 +288,18 @@ private void inflate() {
                         }
                         default:
                             // 10xx xxxx,  1111 xxxx
-                            throw new CpException("malformed input around byte " + px);
+                            throw malformedInput(px);
                     }
                 }
                 this.hash = hashString(hash);
                 charLen = chararr_count;
                 this.chars = chararr;
                 state = State.CHAR;
             }
+        }
 
+        private ConstantPoolException malformedInput(int px) {
+            return new ConstantPoolException("#%d: malformed modified UTF8 around byte %d".formatted(index(), px));
         }
 
         @Override
@@ -1134,12 +1138,4 @@ public boolean equals(Object o) {
             return false;
         }
     }
-
-    static class CpException extends RuntimeException {
-        static final long serialVersionUID = 32L;
-
-        CpException(String s) {
-            super(s);
-        }
-    }
 }