[JENA-1919] ArrayIndexOutOfBounds in BufferingWriter.java

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Jena 3.15.0
• Fix Version/s: Jena 3.16.0
• Component/s: Base
• Assignee: Andy Seaborne
• Reporter: Matt Hoffman
• Created: 17/Jun/20 19:07
• Updated: 13/Jul/20 15:51
• Resolved: 22/Jun/20 14:35

Description

I observed that the blockSize does not control the actual size of the underlying char array 'buffer' which will result in ArrayIndexOutOfBounds.

Locally I added the test below to TestBufferingWriter.java to illustrate.
  

public void write_07 () {
   String alpha = "0123456789abcdefghijklmnopqrstuvwzyzABCDEFGHIJKLMNOPQRSTUVWZYZ";

    create(8194, 4098);
    Random r = new Random();
    for (int i = 0; i < 8194;i++) {
        w.output(alpha.charAt(r.nextInt(alpha.length())));
    }

    w.close();

    String x = string();
    assertEquals(x.length(), 8194);
}

Which produces.

[ERROR] write_07(org.apache.jena.atlas.io.TestBufferingWriter)  Time elapsed: 0.007 s  <<< ERROR!
java.lang.ArrayIndexOutOfBoundsException: 8192
	at org.apache.jena.atlas.io.TestBufferingWriter.write_07(TestBufferingWriter.java:112)