8353013: java.net.URI.create(String) may have low performance to scan the host/domain name from URI string when the hostname starts with number

src/java.base/share/classes/java/net/URI.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -3426,6 +3426,20 @@ private int scanByte(int start, int n)
             int p = start;
             int q = scan(p, n, L_DIGIT, H_DIGIT);
             if (q <= p) return q;
+
+            // Handle leading zeros
+            int i = p, j;
+            while ((j = scan(i, q, '0')) > i) i = j;
+
+            // Calculate the number of significant digits (after leading zeros)
+            int significantDigitsNum = q - i;
+
+            // If no significant digits (all zeros), the value is 0
+            if (significantDigitsNum < 3)  return q; // definitely < 255
+
+            // If more than 3 significant digits, it's definitely > 255
+            if (significantDigitsNum > 3) return p;
+
             if (Integer.parseInt(input, p, q, 10) > 255) return p;
             return q;
         }

test/jdk/java/net/URI/Test.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -24,7 +24,7 @@
 /* @test
  * @summary Unit test for java.net.URI
  * @bug 4464135 4505046 4503239 4438319 4991359 4866303 7023363 7041800
- *      7171415 6339649 6933879 8037396 8272072 8051627 8297687
+ *      7171415 6339649 6933879 8037396 8272072 8051627 8297687 8353013
  * @author Mark Reinhold
  */
 
@@ -1620,6 +1620,7 @@ static void bugs() {
         b8051627();
         b8272072();
         b8297687();
+        b8353013();
     }
 
     private static void b8297687() {
@@ -1786,6 +1787,28 @@ private static void b8272072() {
         }
     }
 
+    // 8353013 - java.net.URI.create(String) may have low performance to scan the host/domain name from
+    //           URI string when the hostname starts with number
+    private static void b8353013() {
+        testCreate("https://0.0.0.1").s("https").h("0.0.0.1").p("").z();
+        testCreate("https://00.0.0.2").s("https").h("00.0.0.2").p("").z();
+        testCreate("https://000.0.0.3").s("https").h("000.0.0.3").p("").z();
+        testCreate("https://0000.0.0.4").s("https").h("0000.0.0.4").p("").z();
+
+        testCreate("https://00000.0.0.5").s("https").h("00000.0.0.5").p("").z();
+        testCreate("https://00001.0.0.6").s("https").h("00001.0.0.6").p("").z();
+
+        testCreate("https://01.0.0.1").s("https").h("01.0.0.1").p("").z();
+
+        testCreate("https://111111.2.3.com").s("https").h("111111.2.3.com").p("").z();
+
+        testCreate("https://1.example.com").s("https").h("1.example.com").p("").z();
+        testCreate("https://12.example.com").s("https").h("12.example.com").p("").z();
+        testCreate("https://123.example.com").s("https").h("123.example.com").p("").z();
+        testCreate("https://1234.example.com").s("https").h("1234.example.com").p("").z();
+        testCreate("https://12345.example.com").s("https").h("12345.example.com").p("").z();
+    }
+
     public static void main(String[] args) throws Exception {
         switch (args.length) {