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  1. JDK
  2. JDK-8218227

StringBuilder/StringBuffer constructor throws confusing NegativeArraySizeException

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Details

    • Bug
    • Resolution: Fixed
    • P4
    • 13
    • None
    • core-libs
    • None
    • b07

    Description

      Two StringBuilder​ constructors that take String or CharSequence argument throw a confusing NegativeArraySizeException if the argument is extremely large.

      This is because the constructor tries to set the initial capacity equal to the length of the argument + 16 (this is specified in the spec, actually).
      When the argument's length is > (Integer.MAX_VALUE - 16), the initial capacity becomes negative due to the integer overflow.

      public class T {
          public static void main(String[] args) {
              // 0, 1 -> cannot create str
              // 2, ..., 15 -> confising NegativeArraySizeException
              // 16, 17 -> OOM in StringBuilder
              // 18 and more -> Ok
              int DELTA = 10;

              String str = "Z".repeat(Integer.MAX_VALUE - DELTA);
              StringBuilder sb = new StringBuilder(str);
          }
      }

      It would be more accurate to throw OutOfMemoryError in such cases.

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              igerasim Ivan Gerasimov
              igerasim Ivan Gerasimov
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                Created:
                Updated:
                Resolved: