Spring cache defaults to hashcode based cache key for multiple arguments [SPR-10688]

[spring-projects-issues]

Lance S opened SPR-10688 and commented

If I add a @Cacheable("cachename") annotation to a method with multiple arguments and I don't specify a key, Spring will create a cache key for me. This cache key is a hash of the arguments. Since a hash is not guaranteed to be unique, I think that this is a dangerous default which will cause errors (although the errors will be rare).

For example:
Long.valueOf(0) and Long.valueOf(-1) both have 0 as their hashcode.

I have attached a failing test case. The test case fails the final assertion

org.junit.ComparisonFailure: expected:<0:[-1]> but was:<0:[0]>
	at org.junit.Assert.assertEquals(Assert.java:123)
	at org.junit.Assert.assertEquals(Assert.java:145)
	at foo.bar.SpringCacheBrokenTest.testCache(SpringCacheBrokenTest.java:52)

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Attachments:

• SpringCacheBrokenTest.java (1.72 kB)

Issue Links:

• Cacheable key collision with DefaultKeyGenerator [SPR-10237] #14870 Cacheable key collision with DefaultKeyGenerator ("duplicates")

[spring-projects-issues]

Phil Webb commented

This issue has recently been addressed with #14870 and the default behavior will change with Spring 4.0.