
You do need to learn how to find information from the API
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Piscis Babelis est parvus, flavus, et hiridicus, et est probabiliter insolitissima raritas in toto mundo.
Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius  and a lot of courage  to move in the opposite direction.  Ernst F. Schumacher
looking for coding examples
public interface Comparable
This interface imposes a total ordering on the objects of each class that implements it. This ordering is referred to as the class's natural ordering, and the class's compareTo method is referred to as its natural comparison method.
Lists (and arrays) of objects that implement this interface can be sorted automatically by Collections.sort (and Arrays.sort). Objects that implement this interface can be used as keys in a sorted map or elements in a sorted set, without the need to specify a comparator.
A class's natural ordering is said to be consistent with equals if and only if (e1.compareTo((Object)e2)==0) has the same boolean value as e1.equals((Object)e2) for every e1 and e2 of class C.
It is strongly recommended (though not required) that natural orderings be consistent with equals. This is so because sorted sets (and sorted maps) without explicit comparators behave "strangely" when they are used with elements (or keys) whose natural ordering is inconsistent with equals. In particular, such a sorted set (or sorted map) violates the general contract for set (or map), which is defined in terms of the equals operation.
For example, if one adds two keys a and b such that (a.equals((Object)b) && a.compareTo((Object)b) != 0) to a sorted set that does not use an explicit comparator, the second add operation returns false (and the size of the sorted set does not increase) because a and b are equivalent from the sorted set's perspective.
Virtually all Java core classes that implement comparable have natural orderings that are consistent with equals. One exception is java.math.BigDecimal, whose natural ordering equates BigDecimals with equal values and different precisions (such as 4.0 and 4.00).
For the mathematically inclined, the relation that defines the natural ordering on a given class C is:
{(x, y) such that x.compareTo((Object)y) <= 0}.
The quotient for this total order is:
{(x, y) such that x.compareTo((Object)y) == 0}.
It follows immediately from the contract for compareTo that the quotient is an equivalence relation on C, and that the natural ordering is a total order on C. When we say that a class's natural ordering is consistent with equals, we mean that the quotient for the natural ordering is the equivalence relation defined by the class's equals(Object) method:
{(x, y) such that x.equals((Object)y)}.
doco
Piscis Babelis est parvus, flavus, et hiridicus, et est probabiliter insolitissima raritas in toto mundo.
Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius  and a lot of courage  to move in the opposite direction.  Ernst F. Schumacher
doco
doco
I Hope This Helps
Carl Trusiak, SCJP2, SCWCD
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