RFR: 8295153: java/util/Base64/TestEncodingDecodingLength.java ran out of memory

[Lance Andersen]

On Wed, 1 May 2024 16:10:06 GMT, Justin Lu <jlu at openjdk.org> wrote:

> Please review this PR which converts _TestEncodingDecodingLength.java_ into a whitebox test which allows for testing to be done without memory usage issues.
> 
> Currently, the test requires about ~2.75 `Integer.MAX_VALUE` sized byte arrays worth of memory. (2 for the initial array allocation, .75 for the target array in `decode()`). While the `-Xms6g -Xmx8g` options should address this, there have been intermittent memory issues, as the underlying machine machine may be running other tests simultaneously.
> 
> By converting this test to a white-box test not only does it get rid of memory issues, but it also gets rid of the need to decode 2GB of data 3 times. The change is done using reflection to test the private visibility methods `encodedOutLength` and `decodedOutLength`, which the public `encode` and `decode` overloaded methods call respectively.

Thank you for taking this on Justin and converting to a junit test as part of your updates.

Overall it looks good on an initial pass.

Please see a few suggestions for your consideration

test/jdk/java/util/Base64/TestEncodingDecodingLength.java line 47:

> 45: public class TestEncodingDecodingLength {
> 46: 
> 47:     private static final int size = Integer.MAX_VALUE - 8;

Perhaps consider size-> SIZE and maybe tweak the name and add an additional comment to its purpose

test/jdk/java/util/Base64/TestEncodingDecodingLength.java line 67:

> 65: 
> 66:         // OOME case
> 67:         try {

Perhaps make this a separate test case so that the IAE test fails the OOME still runs

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PR Review: https://git.openjdk.org/jdk/pull/19036#pullrequestreview-2033944705
PR Review Comment: https://git.openjdk.org/jdk/pull/19036#discussion_r1586493998
PR Review Comment: https://git.openjdk.org/jdk/pull/19036#discussion_r1586499085