THE Java™ Programming Language, Fourth Edition

The types higher up the type hierarchy are said to be wider, or less specific, than the types lower down the hierarchy. The lowe ...

3.4.3. Testing for Type You can test the class of an object by using the instanceof operator, which evaluates to true if the exp ...

this.element = element; } public Cell getNext() { return next; } public void setNext(Cell next) { this.next = next; } } A queue ...

} But this code won't compile. The problem is that the class attempting to access the protected member is PriorityQueue while th ...

others. If you make anything final, be sure that you want to create these restrictions. In many cases, you can achieve the secur ...

the "Template Method" pattern. In many cases the expertise methods are good candidates for being final so that the expertise can ...

Exercise 3.5: Write a new extended class that benchmarks something else, such as how long it takes to run a loop from zero to so ...

Finalizes the object during garbage collection. This method is discussed in detail in "Finalization" on page 449. public Stringt ...

[3]Cloneable should have been spelled Clonable, but the misspelling was realized too late to be fixed. The clone method implemen ...

3.9.2. Correct Cloning Objects of most classes can be cloned in principle. Even if your class does not support the Cloneable int ...

Now consider what happens when future code invokes first.pop(), followed by first.push(17). The top element in the stack first w ...

Object.clone will achieve this. If copying the value is not appropriate for the field then it cannot be declared final. In this ...

creates a new kind of object that "is a" kind of the original class. The IsA relationship is quite different from a HasA relatio ...

actions that can be performed on those fields can be done via the public methods that Attr provides. On the other hand, making t ...

curMetrics.compareCnt++; double d1 = values[i]; double d2 = values[j]; if (d1 == d2) return 0; else return (d1 < d2? -1 : 1); ...

// default mechanism works return (SortMetrics) super.clone(); } catch (CloneNotSupportedException e) { // can't happen: this an ...

Now with these classes as examples, let us return to the issue of designing a class to be extended. We carefully designed the pr ...

them? 3.12. Single Inheritance versus Multiple Inheritance A new class can extend exactly one superclass, a model known as singl ...

to define a type without defining a class. Interfaces define types in an abstract form as a collection of methods or other types ...

Consider a variation of the Point class we introduced in Chapter 1. The natural ordering for points could be their distance from ...