# HG changeset patch
# User igerasim
# Date 1565222180 25200
#      Wed Aug 07 16:56:20 2019 -0700
# Node ID 5ad49c966f1f1a0e70d608fb546cd5b68960208f
# Parent  314e62bbdb168fd89fe37ba57519dcd0129c805f
[mq]: 8221307-String-substring-OOB-exception-on-start-index-reports-improper-information

diff --git a/src/java.base/share/classes/java/lang/String.java b/src/java.base/share/classes/java/lang/String.java
--- a/src/java.base/share/classes/java/lang/String.java
+++ b/src/java.base/share/classes/java/lang/String.java
@@ -1868,15 +1868,16 @@
      *             length of this {@code String} object.
      */
     public String substring(int beginIndex) {
-        if (beginIndex < 0) {
-            throw new StringIndexOutOfBoundsException(beginIndex);
-        }
         int subLen = length() - beginIndex;
-        if (subLen < 0) {
-            throw new StringIndexOutOfBoundsException(subLen);
-        }
-        if (beginIndex == 0) {
-            return this;
+        if (beginIndex <= 0 || subLen <= 0) {
+            if (beginIndex == 0) {
+                return this;
+            }
+            if (subLen == 0) {
+                return "";
+            }
+            throw new StringIndexOutOfBoundsException(
+                "begin " + beginIndex + ", length " + length());
         }
         return isLatin1() ? StringLatin1.newString(value, beginIndex, subLen)
                           : StringUTF16.newString(value, beginIndex, subLen);