Classes and objects in Java must be initialized before they are used. You’ve previously learned that class fields are initialized to default values when classes are loaded, and that objects are ...

Java’s equals() and hashcode() are two methods that work together to verify if two objects have the same value. You can use them to make object comparisons easy and efficient in your Java programs.

However, the Java Platform provides a data structure that greatly simplifies the use of reference objects like this, called the java.util.WeakHashMap class.