在 Java 6 中编译，在 7 中运行 - 如何指定 useLegacyMergeSort？
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Compile in Java 6, run in 7 - how to specify useLegacyMergeSort?
提问by Alex
I'm wondering if I compile in Java 6, but someone runs the program on Java 7, will the Java 6 or 7 version of Arrays.sort be used?
我想知道我是否在 Java 6 中编译，但有人在 Java 7 上运行该程序，是否会使用 Java 6 或 7 版本的 Arrays.sort？
It's important because the new mergesort throws an IllegalArgumentException, and the old one doesn't (see Comparison method violates its general contract! Java 7 only)
这很重要，因为新的归并排序会抛出 IllegalArgumentException，而旧的则不会（请参阅比较方法违反其一般约定！仅限 Java 7）
Now, it's possible to compile in Java 7 using Arrays.useLegacyMergeSort, but obviously that flag isn't available for Java 6 - and we want to be compatible on Mac OS Snow Leopard (which uses 6).
现在，可以使用 Arrays.useLegacyMergeSort 在 Java 7 中进行编译，但显然该标志不适用于 Java 6 - 我们希望与 Mac OS Snow Leopard（使用 6）兼容。
For some reason (see http://madbean.com/2006/target14/) the -target compiler flag doesn't seem to produce compatible code, so we'd rather compile in Java 6.
出于某种原因（请参阅http://madbean.com/2006/target14/） -target 编译器标志似乎无法生成兼容的代码，因此我们宁愿在 Java 6 中进行编译。
Any suggestions?
有什么建议？
回答by Evgeniy Dorofeev
try to set system property
尝试设置系统属性
java -Djava.util.Arrays.useLegacyMergeSort=true ...
java -Djava.util.Arrays.useLegacyMergeSort=true ...
Note that it's not from Arrays public API but from src
请注意，它不是来自 Arrays 公共 API，而是来自 src
/**
* Old merge sort implementation can be selected (for
* compatibility with broken comparators) using a system property.
* Cannot be a static boolean in the enclosing class due to
* circular dependencies. To be removed in a future release.
*/
static final class LegacyMergeSort {
private static final boolean userRequested =
java.security.AccessController.doPrivileged(
new sun.security.action.GetBooleanAction(
"java.util.Arrays.useLegacyMergeSort")).booleanValue();
}
