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Diffstat (limited to 'java/10-collections/hashcode-contract.txt')
| -rw-r--r-- | java/10-collections/hashcode-contract.txt | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/java/10-collections/hashcode-contract.txt b/java/10-collections/hashcode-contract.txt new file mode 100644 index 0000000..2ed248c --- /dev/null +++ b/java/10-collections/hashcode-contract.txt @@ -0,0 +1,15 @@ + Whenever it is invoked on the same object more than once during an execu- + tion of a Java application, the hashCode() method must consistently return + the same integer, provided no information used in equals() comparisons + on the object is modified. This integer need not remain consistent from one + execution of an application to another execution of the same application. + + If two objects are equal according to the equals(Object) method, then + calling the hashCode() method on each of the two objects must produce the + same integer result. + + It is NOT required that if two objects are unequal according to the + equals(java.lang.Object) method, then calling the hashCode() method + on each of the two objects must produce distinct integer results. However, + the programmer should be aware that producing distinct integer results for + unequal objects may improve the performance of hashtables. |