"Comparison Method violates it's general contract!" Crash

[Hellfish]

Just an infodump while I wrestle with the branch reintegration of AbilityWork.

This crash is a result of the stricter approach of Java 1.7 to non-transitive comparison methods (ie if A >= B and B >= C is true then A >= C should be true but isn't). The error isn't actually in our code but in Swing's LayoutFocusTraversalPolicy class, as I understand it, and is apparently a regression in 1.7 (1.5 apparently also had this problem, so 1.6 is the sweet-spot). LayoutFocusTraversalPolicy handles in which order UI components should recieve focus. The latest bug report I've found on this was closed as not reproducible.

Two solutions I've found in old threads and bug reports are:

• Setting the System Property "java.util.Arrays.useLegacyMergeSort" to true via System.setProperty(). Pros: Easily done. Cons: May create issues elsewhere, not 100% certain to fix the problem, more of a workaround than a fix.
• Writing one or (more likely) several custom FocusTraversalPolicies for each panel with multiple components. Pros: Likely more robust. Cons: Not sure how much work this would need (probably quite a bit), possibly overkill.

[friarsol]

Two solutions I've found in old threads and bug reports are:

• Setting the System Property "java.util.Arrays.useLegacyMergeSort" to true via System.setProperty(). Pros: Easily done. Cons: May create issues elsewhere, not 100% certain to fix the problem, more of a workaround than a fix.
• Writing one or (more likely) several custom FocusTraversalPolicies for each panel with multiple components. Pros: Likely more robust. Cons: Not sure how much work this would need (probably quite a bit), possibly overkill.

I'm not sure if changing to Merge Sort will create other issues, TimSort is faster, but that doesn't mean that Merge sort is a slouch

http://news.ycombinator.com/item?id=752677

We're probably better off using the Legacy Merge Sort until it makes sense to handling the traversal policies (if that's the right thing to do).

[Max mtg]

The largest collection to sort in our game is a collection of all the cards with as many as 20k records, so I don't think the "legacy" Merge sort would create any performance problem. To my mind, its completelly safe to set the mentioned property to true.

[Hellfish]

I went ahead and added the property setting to startup. If there is a problem it oughta rear it's ugly head before next beta.

[moomarc]

I went ahead and added the property setting to startup. If there is a problem it oughta rear it's ugly head before next beta.

now we just need someone with java 1.7 to playtest it and see if it fixes those bugs.