[Bug classpath/61468] New: StringBuilder.setLength() doesn't clear string data

[zuencap at yahoo dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61468

            Bug ID: 61468
           Summary: StringBuilder.setLength() doesn't clear string data
           Product: classpath
           Version: 0.98
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: classpath
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zuencap at yahoo dot com

This test fails:

StringBuilder s = new StringBuilder("StringBuilder");
s.setLength(5);
s.setLength(13);
assertEquals("Strin\000\000\000\000\000\000\000\000", s.toString());

Recommended fix:
public void setLength(int newLength) {
    if (newLength < 0)
        throw new StringIndexOutOfBoundsException(newLength);

    if( newLength > value.length ) {
        /* If the StringBuilder's value needs to grow, then we know that
           value will be newly allocated and the region between count and
           newLength wil be filled with '\0'.  */
        ensureCapacity(newLength);
    } else {
        /* The StringBuilder's value doesn't need to grow.  However,
           we should clear out any cruft that may exist.  */
        while (count < newLength) {
            value[count++] = '\0';
        }
        // if count > newLength, it will be set to newLength at the end
    }

    count = newLength;
}