Uploaded image for project: 'JDK'
  1. JDK
  2. JDK-8356152

String.concat can throw StringIndexOutOfBoundsException

XMLWordPrintable

    • Icon: Bug Bug
    • Resolution: Unresolved
    • Icon: P4 P4
    • None
    • 24
    • core-libs
    • None
    • In Review
    • 24

      The following code:

          String r1 = "-".repeat(Integer.MAX_VALUE - 10);
          String r2 = "ы".repeat((Integer.MAX_VALUE - 10) / 2);
          System.out.println(r1.concat(r2));

      On JDK 24 it gives:
      Exception in thread "main" java.lang.StringIndexOutOfBoundsException:
      Range [0, 0 + 2147483637) out of bounds for length 1073741807
          at java.base/jdk.internal.util.Preconditions$1.apply(Preconditions.java:55)
          at java.base/jdk.internal.util.Preconditions$1.apply(Preconditions.java:52)
          at java.base/jdk.internal.util.Preconditions$4.apply(Preconditions.java:213)
          at java.base/jdk.internal.util.Preconditions$4.apply(Preconditions.java:210)
          at java.base/jdk.internal.util.Preconditions.outOfBounds(Preconditions.java:98)
          at java.base/jdk.internal.util.Preconditions.outOfBoundsCheckFromIndexSize(Preconditions.java:118)
          at java.base/jdk.internal.util.Preconditions.checkFromIndexSize(Preconditions.java:397)
          at java.base/java.lang.String.checkBoundsOffCount(String.java:4938)
          at java.base/java.lang.StringUTF16.checkBoundsOffCount(StringUTF16.java:1789)
          at java.base/java.lang.StringUTF16.inflate(StringUTF16.java:1616)
          at java.base/java.lang.StringLatin1.inflate(StringLatin1.java:875)
          at java.base/java.lang.String.getBytes(String.java:4812)
          at java.base/java.lang.StringConcatHelper.doConcat(StringConcatHelper.java:434)
          at java.base/java.lang.String.concat(String.java:2977)

      On JDK 23 it results in expected OOM:

      Exception in thread "main" java.lang.OutOfMemoryError: Overflow:
      String length out of range
          at java.base/java.lang.StringConcatHelper.checkOverflow(StringConcatHelper.java:66)
          at java.base/java.lang.StringConcatHelper.mix(StringConcatHelper.java:125)
          at java.base/java.lang.StringConcatHelper.simpleConcat(StringConcatHelper.java:374)
          at java.base/java.lang.String.concat(String.java:2990)

            rgiulietti Raffaello Giulietti
            aturbanov Andrey Turbanov
            Votes:
            0 Vote for this issue
            Watchers:
            4 Start watching this issue

              Created:
              Updated: