Constructor References A constructor reference is similar to a static method reference, but with the keyword new instead of the static method name, signifying that a constructor of the specified [...]
15.3 Lists Lists are collections that maintain their elements in order and can contain duplicates. The elements in a list are ordered. Each element, therefore, has a position in the [...]
The ArrayList<E>, LinkedList<E>, and Vector<E> Classes Three implementations of the List<E> interface are provided in the java.util package: ArrayList<E>, LinkedList<E>, and Vector<E>. The ArrayList<E> class implements the List<E> interface (Chapter [...]
15.4 Sets The Java Collections Framework provides the Set<E> interface to model the mathematical set abstraction. The Set<E> Interface Unlike other implementations of the Collection<E> interface, implementations of the Set<E> [...]
14.1 The Objects Class The following static methods of the java.util.Objects class are convenient to use when comparing objects and computing the hash code for an object. They take away [...]
Checklist for Implementing the equals() Method Example 14.3 shows an implementation of the equals() method for version numbers. Next, we provide a checklist for implementing the equals() method. Method Overriding [...]
Transitivity If two classes, A and B, have a bilateral agreement on their objects being equal, then this rule guarantees that one of them, say B, does not enter into [...]
Field Comparisons Equivalence comparison involves comparing relevant fields from both objects to determine if their logical states match. For fields that are of primitive data types, their primitive values can [...]
General Contract of the hashCode() Method The general contract of the hashCode() method stipulates the following: Note that the hash code contract does not imply that objects with equal hash [...]
14.3 Implementing the hashCode() Method Hashing is an efficient technique for storing and retrieving data. A common hashing scheme uses an array where each element is a list of items. [...]