[SLING-2975] MapEntry#compareTo method is not consistent and might throw ISE on Java7

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Resource Resolver 1.0.6
• Fix Version/s: Resource Resolver 1.1.0
• Component/s: ResourceResolver
• Assignee: Carsten Ziegeler
• Reporter: Carsten Ziegeler
• Created: 18/Jul/13 11:02
• Updated: 04/Apr/14 09:05
• Resolved: 18/Jul/13 11:06

Description

On Java7 sorting the map entries might result in an IllegalStateException:
java.lang.IllegalArgumentException: Comparison method violates its general
contract!
at java.util.ComparableTimSort.mergeLo(ComparableTimSort.java:714)
at java.util.ComparableTimSort.mergeAt(ComparableTimSort.java:451)
at java.util.ComparableTimSort.mergeCollapse(ComparableTimSort.java:376)
at java.util.ComparableTimSort.sort(ComparableTimSort.java:182)
at java.util.ComparableTimSort.sort(ComparableTimSort.java:146)
at java.util.Arrays.sort(Arrays.java:472)
at java.util.Collections.sort(Collections.java:155)

The behaviour of sorting has changed with Java7 (see http://stackoverflow.com/questions/7849539/comparison-method-violates-its-general-contract-java-7-only) and it now throws such an exception if the compare method is not implemented in an consistent way.

In our case: if the two strings have the same lengths, always 1 is returned, so compareTo("a", "b") returns 1 while compareTo("b", "a") returns 1 as well