jdk7 中Collections.sort 异常

Collections.sort 异常

java.lang.IllegalArgumentException: Comparison method violates its general contract!
        at java.util.TimSort.mergeHi(TimSort.java:868)
        at java.util.TimSort.mergeAt(TimSort.java:485)
        at java.util.TimSort.mergeForceCollapse(TimSort.java:426)
        at java.util.TimSort.sort(TimSort.java:223)
        at java.util.TimSort.sort(TimSort.java:173)
        at java.util.Arrays.sort(Arrays.java:659)
        at java.util.Collections.sort(Collections.java:217)

代码例如以下：

Collections.sort(values, new Comparator<Map.Entry<String, Float>>() {    
<span style="white-space:pre">	</span>public int compare(Map.Entry<String, Float> o1, Map.Entry<String, Float> o2) {  
	<span style="white-space:pre">	</span>return (o2.getValue() > o1.getValue() ? 1 : -1);   
	}   
}); 

是对一个Map数组进行排序，更新了jdk版本号后报以上异常，查询了先关资料后，改动了代码例如以下：

Collections.sort(values, new Comparator<Map.Entry<String, Float>>() {    
	public int compare(Map.Entry<String, Float> o1, Map.Entry<String, Float> o2) {  
		return o2.getValue().compareTo(o1.getValue());
	}   
}); 

异常解决，參考链接：

http://stackoverflow.com/questions/10234038/compare-method-throw-exception-comparison-method-violates-its-general-contract