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Core Java, Volume I: Fundamentals, 12th EditionCore Java, Volume I: Fundamentals, 12th Edition

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This chapter is from the book

This chapter is from the book

Core Java, Volume I: Fundamentals, 12th EditionCore Java, Volume I: Fundamentals, 12th Edition

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6.3 Inner Classes

An inner class is a class that is defined inside another class. Why would you want to do that? There are two reasons:

  • Inner classes can be hidden from other classes in the same package.

  • Inner class methods can access the data from the scope in which they are defined—including the data that would otherwise be private.

Inner classes used to be very important for concisely implementing callbacks, but nowadays lambda expressions do a much better job. Still, inner classes can be very useful for structuring your code. The following sections walk you through all the details.

C++ NOTE

C++ has nested classes. A nested class is contained inside the scope of the enclosing class. Here is a typical example: A linked list class defines a class to hold the links, and a class to define an iterator position.

class LinkedList
{
public:
   class Iterator // a nested class
   {
   public:
      void insert(int x);
      int erase();
      . . .
   private:
      Link* current;
      LinkedList* owner;
   };
   . . .
private:
   Link* head;
   Link* tail;
};

Nested classes are similar to inner classes in Java. However, the Java inner classes have an additional feature that makes them richer and more useful than nested classes in C++. An object that comes from an inner class has an implicit reference to the outer class object that instantiated it. Through this pointer, it gains access to the total state of the outer object. For example, in Java, the Iterator class would not need an explicit pointer to the LinkedList into which it points.

In Java, static inner classes do not have this added pointer. They are the Java analog to nested classes in C++.

6.3.1 Use of an Inner Class to Access Object State

The syntax for inner classes is rather complex. For that reason, I present a simple but somewhat artificial example to demonstrate the use of inner classes. Let’s refactor the TimerTest example and extract a TalkingClock class. A talking clock is constructed with two parameters: the interval between announcements and a flag to turn beeps on or off.

public class TalkingClock
{
   private int interval;
   private boolean beep;

   public TalkingClock(int interval, boolean beep) { . . . }
   public void start() { . . . }

   public class TimePrinter implements ActionListener
      // an inner class
   {
      . . .
   }
}

Note that the TimePrinter class is now located inside the TalkingClock class. This does not mean that every TalkingClock has a TimePrinter instance field. As you will see, the TimePrinter objects are constructed by methods of the TalkingClock class.

Here is the TimePrinter class in greater detail. Note that the actionPerformed method checks the beep flag before emitting a beep.

public class TimePrinter implements ActionListener
{
   public void actionPerformed(ActionEvent event)
   {
      System.out.println("At the tone, the time is "
         + Instant.ofEpochMilli(event.getWhen()));
      if (beep) Toolkit.getDefaultToolkit().beep();
   }
}

Something surprising is going on. The TimePrinter class has no instance field or variable named beep. Instead, beep refers to the field of the TalkingClock object that created this TimePrinter. As you can see, an inner class method gets to access both its own instance fields and those of the outer object creating it.

For this to work, an object of an inner class always gets an implicit reference to the object that created it (see Figure 6.3).

FIGURE 6.3

Figure 6.3 An inner class object has a reference to an outer class object.

This reference is invisible in the definition of the inner class. However, to illuminate the concept, let us call the reference to the outer object outer. Then the actionPerformed method is equivalent to the following:

public void actionPerformed(ActionEvent event)
{
   System.out.println("At the tone, the time is "
      + Instant.ofEpochMilli(event.getWhen()));
   if (outer.beep) Toolkit.getDefaultToolkit().beep();
}

The outer class reference is set in the constructor. The compiler modifies all inner class constructors, adding a parameter for the outer class reference. The TimePrinter class defines no constructors; therefore, the compiler synthesizes a no-argument constructor, generating code like this:

public TimePrinter(TalkingClock clock) // automatically generated code
{
   outer = clock;
}

Again, please note that outer is not a Java keyword. We just use it to illustrate the mechanism involved in an inner class.

When a TimePrinter object is constructed in the start method, the compiler passes the this reference to the current talking clock into the constructor:

var listener = new TimePrinter(this); // parameter automatically added

Listing 6.7 shows the complete program that tests the inner class. Have another look at the access control. Had the TimePrinter class been a regular class, it would have needed to access the beep flag through a public method of the TalkingClock class. Using an inner class is an improvement. There is no need to provide accessors that are of interest only to one other class.

NOTE

We could have declared the TimePrinter class as private. Then only TalkingClock methods would be able to construct TimePrinter objects. Only inner classes can be private. Regular classes always have either package or public access.

Listing 6.7 innerClass/InnerClassTest.java

 1 package innerClass;
 2
 3 import java.awt.*;
 4 import java.awt.event.*;
 5 import java.time.*;
 6
 7 import javax.swing.*;
 8
 9 /**
10  * This program demonstrates the use of inner classes.
11  * @version 1.11 2017-12-14
12  * @author Cay Horstmann
13  */
14 public class InnerClassTest
15 {
16    public static void main(String[] args)
17    {
18       var clock = new TalkingClock(1000, true);
19       clock.start();
20
21       // keep program running until the user selects "OK"
22       JOptionPane.showMessageDialog(null, "Quit program?");
23       System.exit(0);
24    }
25 }
26
27 /**
28  * A clock that prints the time in regular intervals.
29  */
30  class TalkingClock
31  {
32     private int interval;
33     private boolean beep;
34
35     /**
36      * Constructs a talking clock
37      * @param interval the interval between messages (in milliseconds)
38      * @param beep true if the clock should beep
39      */
40     public TalkingClock(int interval, boolean beep)
41     {
42        this.interval = interval;
43        this.beep = beep;
44     }
45
46     /**
47      * Starts the clock.
48      */
49     public void start()
50     {
51        var listener = new TimePrinter();
52        var timer = new Timer(interval, listener);
53        timer.start();
54     }
55
56     public class TimePrinter implements ActionListener
57     {
58        public void actionPerformed(ActionEvent event)
59        {
60           System.out.println("At the tone, the time is "
61              + Instant.ofEpochMilli(event.getWhen()));
62           if (beep) Toolkit.getDefaultToolkit().beep();
63        }
64     }
65  }

6.3.2 Special Syntax Rules for Inner Classes

In the preceding section, we explained the outer class reference of an inner class by calling it outer. Actually, the proper syntax for the outer reference is a bit more complex. The expression

OuterClass.this

denotes the outer class reference. For example, you can write the actionPerformed method of the TimePrinter inner class as

public void actionPerformed(ActionEvent event)
{
   . . .
   if (TalkingClock.this.beep) Toolkit.getDefaultToolkit().beep();
}

Conversely, you can write the inner object constructor more explicitly, using the syntax

outerObject.new InnerClass(construction parameters)

For example:

ActionListener listener = this.new TimePrinter();

Here, the outer class reference of the newly constructed TimePrinter object is set to the this reference of the method that creates the inner class object. This is the most common case. As always, the this. qualifier is redundant. However, it is also possible to set the outer class reference to another object by explicitly naming it. For example, since TimePrinter is a public inner class, you can construct a TimePrinter for any talking clock:

var jabberer = new TalkingClock(1000, true);
TalkingClock.TimePrinter listener = jabberer.new TimePrinter();

Note that you refer to an inner class as

OuterClass.InnerClass

when it occurs outside the scope of the outer class.

NOTE

Any static fields declared in an inner class must be final and initialized with a compile-time constant. If the field was not a constant, it might not be unique.

An inner class cannot have static methods. The Java Language Specification gives no reason for this limitation. It would have been possible to allow static methods that only access static fields and methods from the enclosing class. Apparently, the language designers decided that the complexities outweighed the benefits.

6.3.3 Are Inner Classes Useful? Actually Necessary? Secure?

When inner classes were added to the Java language in Java 1.1, many programmers considered them a major new feature that was out of character with the Java philosophy of being simpler than C++. The inner class syntax is undeniably complex. (It gets more complex as we study anonymous inner classes later in this chapter.) It is not obvious how inner classes interact with other features of the language, such as access control and security.

Inner classes are translated into regular class files with $ (dollar signs) separating the outer and inner class names. For example, the TimePrinter class inside the TalkingClock class is translated to a class file TalkingClock$TimePrinter.class. To see this at work, try the following experiment: run the ReflectionTest program of Chapter 5, and give it the class TalkingClock$TimePrinter to reflect upon. Alternatively, simply use the javap utility:

javap -private ClassName

NOTE

If you use UNIX, remember to escape the $ character when you supply the class name on the command line. That is, run the ReflectionTest or javap program as

java --classpath .:../v1ch05 reflection.ReflectionTest    innerClass.TalkingClock\$TimePrinter

or

javap -private innerClass.TalkingClock\$TimePrinter

You will get the following printout:

public class innerClass.TalkingClock$TimePrinter
      implements java.awt.event.ActionListener
{
   final innerClass.TalkingClock this$0;
   public innerClass.TalkingClock$TimePrinter(innerClass.TalkingClock);
   public void actionPerformed(java.awt.event.ActionEvent);
}

You can plainly see that the compiler has generated an additional instance field, this$0, for the reference to the outer class. (The name this$0 is synthesized by the compiler—you cannot refer to it in your code.) You can also see the TalkingClock parameter for the constructor.

If the compiler can automatically do this transformation, couldn’t you simply program the same mechanism by hand? Let’s try it. We would make TimePrinter a regular class, outside the TalkingClock class. When constructing a TimePrinter

object, we pass it the this reference of the object that is creating it.

class TalkingClock
{
   . . .
   public void start()
   {
      var listener = new TimePrinter(this);
      var timer = new Timer(interval, listener);
      timer.start();
   }
}

class TimePrinter implements ActionListener
{
   private TalkingClock outer;
   . . .
   public TimePrinter(TalkingClock clock)
   {
      outer = clock;
   }
}

Now let us look at the actionPerformed method. It needs to access outer.beep.

if (outer.beep) . . . // ERROR

Here we run into a problem. The inner class can access the private data of the outer class, but our external TimePrinter class cannot.

Thus, inner classes are genuinely more powerful than regular classes because they have more access privileges.

You may well wonder how inner classes manage to acquire those added access privileges. Before Java 11, inner classes were purely a phenomenon of the compiler, and the virtual machine did not have any special knowledge about them. In those days, spying on the TalkingClock class with the ReflectionTest program or with javap and the -private option showed:

class TalkingClock
{
   private int interval;
   private boolean beep;

   public TalkingClock(int, boolean);

   static boolean access$0(TalkingClock); // Prior to Java 11
   public void start();
}

Notice the static access$0 method that the compiler added to the outer class. It returns the beep field of the object that is passed as a parameter. (The method name might be slightly different, such as access$000, depending on the compiler.)

That was a potential security risk, and it made life complicated for tools that analyze class files. As of Java 11, the virtual machine understands nesting relationships between classes, and the access methods are no longer generated.

6.3.4 Local Inner Classes

If you look carefully at the code of the TalkingClock example, you will find that you need the name of the type TimePrinter only once: when you create an object of that type in the start method.

In a situation like this, you can define the class locally in a single method.

public void start()
{
   class TimePrinter implements ActionListener
   {
      public void actionPerformed(ActionEvent event)
      {
         System.out.println("At the tone, the time is "
            + Instant.ofEpochMilli(event.getWhen()));
         if (beep) Toolkit.getDefaultToolkit().beep();
      }
   }

   var listener = new TimePrinter();
   var timer = new Timer(interval, listener);
   timer.start();
}

Local classes are never declared with an access specifier (that is, public or private). Their scope is always restricted to the block in which they are declared.

Local classes have one great advantage: They are completely hidden from the outside world—not even other code in the TalkingClock class can access them. No method except start has any knowledge of the TimePrinter class.

6.3.5 Accessing Variables from Outer Methods

Local classes have another advantage over other inner classes. Not only can they access the fields of their outer classes; they can even access local variables! However, those local variables must be effectively final. That means, they may never change once they have been assigned.

Here is a typical example. Let’s move the interval and beep parameters from the TalkingClock constructor to the start method.

public void start(int interval, boolean beep)
{
   class TimePrinter implements ActionListener
   {
      public void actionPerformed(ActionEvent event)
      {
         System.out.println("At the tone, the time is "
            + Instant.ofEpochMilli(event.getWhen()));
         if (beep) Toolkit.getDefaultToolkit().beep();
      }
   }

   var listener = new TimePrinter();
   var timer = new Timer(interval, listener);
   timer.start();
}

Note that the TalkingClock class no longer needs to store a beep instance field. It simply refers to the beep parameter variable of the start method.

Maybe this should not be so surprising. The line

if (beep) . . .

is, after all, ultimately inside the start method, so why shouldn’t it have access to the value of the beep variable?

To see why there is a subtle issue here, let’s consider the flow of control more closely.

  1. The start method is called.

  2. The object variable listener is initialized by a call to the constructor of the inner class TimePrinter.

  3. The listener reference is passed to the Timer constructor, the timer is started, and the start method exits. At this point, the beep parameter variable of the start method no longer exists.

  4. A second later, the actionPerformed method executes if (beep) . . .

For the code in the actionPerformed method to work, the TimePrinter class must have copied the beep field as a local variable of the start method, before the beep parameter value went away. That is indeed exactly what happens. In our example, the compiler synthesizes the name TalkingClock$1TimePrinter for the local inner class. If you use the ReflectionTest program or the javap utility again to spy on the TalkingClock$1TimePrinter class, you will get the following output:

class TalkingClock$1TimePrinter
{
   TalkingClock$1TimePrinter();

   public void actionPerformed(java.awt.event.ActionEvent);

   final boolean val$beep;
   final TalkingClock this$0;
}

When an object is created, the current value of the beep variable is stored in the val$beep field. As of Java 11, this happens with “nest mate” access. Previously, the inner class constructor had an additional parameter to set the field. Either way, the inner class field persists even if the local variable goes out of scope.

6.3.6 Anonymous Inner Classes

When using local inner classes, you can often go a step further. If you want to make only a single object of this class, you don’t even need to give the class a name. Such a class is called an anonymous inner class.

public void start(int interval, boolean beep)
{
   var listener = new ActionListener()
      {
         public void actionPerformed(ActionEvent event)
         {
            System.out.println("At the tone, the time is "
               + Instant.ofEpochMilli(event.getWhen()));
            if (beep) Toolkit.getDefaultToolkit().beep();
         }
      };
   var timer = new Timer(interval, listener);
   timer.start();
}

This syntax is very cryptic indeed. What it means is this: Create a new object of a class that implements the ActionListener interface, where the required method actionPerformed is the one defined inside the braces { }.

In general, the syntax is

new SuperType(construction parameters)
   {
      inner class methods and data
   }

Here, SuperType can be an interface, such as ActionListener; then, the inner class implements that interface. SuperType can also be a class; then, the inner class extends that class.

An anonymous inner class cannot have constructors because the name of a constructor must be the same as the name of a class, and the class has no name. Instead, the construction parameters are given to the superclass constructor. In particular, whenever an inner class implements an interface, it cannot have any construction parameters. Nevertheless, you must supply a set of parentheses as in

new InterfaceType()
   {
      methods and data
   }

You have to look carefully to see the difference between the construction of a new object of a class and the construction of an object of an anonymous inner class extending that class.

var queen = new Person("Mary");
   // a Person object
var count = new Person("Dracula") { . . . };
   // an object of an inner class extending Person

If the closing parenthesis of the construction parameter list is followed by an opening brace, then an anonymous inner class is being defined.

NOTE

Even though an anonymous class cannot have constructors, you can provide an object initialization block:

var count = new Person("Dracula")
   {
      { initialization }
      . . .
   };

Listing 6.8 contains the complete source code for the talking clock program with an anonymous inner class. If you compare this program with Listing 6.7, you will see that in this case, the solution with the anonymous inner class is quite a bit shorter and, hopefully, with some practice, as easy to comprehend.

For many years, Java programmers routinely used anonymous inner classes for event listeners and other callbacks. Nowadays, you are better off using a lambda expression. For example, the start method from the beginning of this section can be written much more concisely with a lambda expression like this:

public void start(int interval, boolean beep)
{
   var timer = new Timer(interval, event ->
      {
         System.out.println(
            "At the tone, the time is " + Instant.ofEpochMilli(event.getWhen()));
         if (beep) Toolkit.getDefaultToolkit().beep();
      });
   timer.start();
}

NOTE

If you store an anonymous class instance in a variable defined with var, the variable knows about added methods or fields:

var bob = new Object() { String name = "Bob"; }
System.out.println(bob.name);

If you declare bob as having type Object, then bob.name does not compile.

The object constructed with new Object() { String name = "Bob"; } has type “Object with a Sting name field.” This is a nondenotable type—a type that you cannot express with Java syntax. Nevertheless, the compiler understands the type, and it can set it as the type for the bob variable.

NOTE

The following trick, called double brace initialization, takes advantage of the inner class syntax. Suppose you want to construct an array list and pass it to a method:

var friends = new ArrayList<String>();
friends.add("Harry");
friends.add("Tony");
invite(friends);

If you don’t need the array list again, it would be nice to make it anonymous. But then how can you add the elements? Here is how:

invite(new ArrayList<String>() {{ add("Harry"); add("Tony"); }});

Note the double braces. The outer braces make an anonymous subclass of ArrayList. The inner braces are an object initialization block (see Chapter 4).

In practice, this trick is rarely useful. More likely than not, the invite method is willing to accept any List<String>, and you can simply pass List.of("Harry", "Tony").

caution.jpg CAUTION

It is often convenient to make an anonymous subclass that is almost, but not quite, like its superclass. But you need to be careful with the equals method. In Chapter 5, I recommended that your equals methods use a test

if (getClass() != other.getClass()) return false;

An anonymous subclass will fail this test.

tip.jpg TIP

When you produce logging or debugging messages, you often want to include the name of the current class, such as

System.err.println("Something awful happened in " + getClass());

But that fails in a static method. After all, the call to getClass calls this.getClass(), and a static method has no this. Use the following expression instead:

new Object(){}.getClass().getEnclosingClass() // gets class of static method

Here, new Object(){} makes an anonymous object of an anonymous subclass of Object, and getEnclosingClass gets its enclosing class—that is, the class containing the static method.

Listing 6.8 anonymousInnerClass/AnonymousInnerClassTest.java

 1 package anonymousInnerClass;
 2
 3 import java.awt.*;
 4 import java.awt.event.*;
 5 import java.time.*;
 6
 7 import javax.swing.*;
 8
 9 /**
10  * This program demonstrates anonymous inner classes.
11  * @version 1.12 2017-12-14
12  * @author Cay Horstmann
13  */
14 public class AnonymousInnerClassTest
15 {
16    public static void main(String[] args)
17    {
18       var clock = new TalkingClock();
19       clock.start(1000, true);
20
21       // keep program running until the user selects "OK"
22       JOptionPane.showMessageDialog(null, "Quit program?");
23       System.exit(0);
24    }
25 }
26
27 /**
28  * A clock that prints the time in regular intervals.
29  */
30 class TalkingClock
31 {
32    /**
33     * Starts the clock.
34     * @param interval the interval between messages (in milliseconds)
35     * @param beep true if the clock should beep
36     */
37    public void start(int interval, boolean beep)
38    {
39       var listener = new ActionListener()
40          {
41              public void actionPerformed(ActionEvent event)
42              {
43                 System.out.println("At the tone, the time is "
44                    + Instant.ofEpochMilli(event.getWhen()));
45                 if (beep) Toolkit.getDefaultToolkit().beep();
46              }
47          };
48       var timer = new Timer(interval, listener);
49       timer.start();
50    }
51 }

6.3.7 Static Inner Classes

Occasionally, you may want to use an inner class simply to hide one class inside another—but you don’t need the inner class to have a reference to the outer class object. You can suppress the generation of that reference by declaring the inner class static.

Here is a typical example of where you would want to do this. Consider the task of computing the minimum and maximum value in an array. Of course, you write one method to compute the minimum and another method to compute the maximum. When you call both methods, the array is traversed twice. It would be more efficient to traverse the array only once, computing both the minimum and the maximum simultaneously.

double min = Double.POSITIVE_INFINITY;
double max = Double.NEGATIVE_INFINITY;
for (double v : values)
{
   if (min > v) min = v;
   if (max < v) max = v;
}

However, the method must return two numbers. We can achieve that by defining a class Pair that holds two values:

class Pair
{
   private double first;
   private double second;

   public Pair(double f, double s)
   {
      first = f;
      second = s;
   }
   public double getFirst() { return first; }
   public double getSecond() {  return second; }
}

The minmax method can then return an object of type Pair.

class ArrayAlg
{
   public static Pair minmax(double[] values)
   {
      . . .
      return new Pair(min, max);
   }
}

The caller of the method uses the getFirst and getSecond methods to retrieve the answers:

Pair p = ArrayAlg.minmax(d);
System.out.println("min = " + p.getFirst());
System.out.println("max = " + p.getSecond());

Of course, the name Pair is an exceedingly common name, and in a large project, it is quite possible that some other programmer had the same bright idea—but made a Pair class that contains a pair of strings. We can solve this potential name clash by making Pair a public inner class inside ArrayAlg. Then the class will be known to the public as ArrayAlg.Pair:

ArrayAlg.Pair p = ArrayAlg.minmax(d);

However, unlike the inner classes used in previous examples, we do not want to have a reference to any other object inside a Pair object. That reference can be suppressed by declaring the inner class static:

class ArrayAlg
{
   public static class Pair
   {
      . . .
   }
   . . .
}

Of course, only inner classes can be declared static. A static inner class is exactly like any other inner class, except that an object of a static inner class does not have a reference to the outer class object that generated it. In our example, we must use a static inner class because the inner class object is constructed inside a static method:

public static Pair minmax(double[] d)
{
   . . .
   return new Pair(min, max);
}

Had the Pair class not been declared as static, the compiler would have complained that there was no implicit object of type ArrayAlg available to initialize the inner class object.

NOTE

Use a static inner class whenever the inner class does not need to access an outer class object. Some programmers use the term nested class to describe static inner classes.

NOTE

Unlike regular inner classes, static inner classes can have static fields and methods.

NOTE

Classes that are declared inside an interface are automatically static and public.

NOTE

Interfaces, records, and enumerations that are declared inside a class are automatically static.

Listing 6.9 contains the complete source code of the ArrayAlg class and the nested Pair class.

Listing 6.9 staticInnerClass/StaticInnerClassTest.java

 1 package staticInnerClass;
 2
 3 /**
 4  * This program demonstrates the use of static inner classes.
 5  * @version 1.02 2015-05-12
 6  * @author Cay Horstmann
 7  */
 8 public class StaticInnerClassTest
 9 {
10    public static void main(String[] args)
11    {
12       var values = new double[20];
13       for (int i = 0; i < values.length; i++)
14          values[i] = 100 * Math.random();
15       ArrayAlg.Pair p = ArrayAlg.minmax(values);
16       System.out.println("min = " + p.getFirst());
17       System.out.println("max = " + p.getSecond());
18    }
19 }
20
21 class ArrayAlg
22 {
23    /**
24     * A pair of floating-point numbers
25     */
26    public static class Pair
27    {
28       private double first;
29       private double second;
30
31     /**
32      * Constructs a pair from two floating-point numbers
33      * @param f the first number
34      * @param s the second number
35      */
36     public Pair(double f, double s)
37     {
38        first = f;
39        second = s;
40     }
41
42     /**
43      * Returns the first number of the pair
44      * @return the first number
45      */
46     public double getFirst()
47     {
48        return first;
49     }
50
51     /**
52      * Returns the second number of the pair
53      * @return the second number
54      */
55     public double getSecond()
56     {
57        return second;
58     }
59   }
60
61   /**
62    * Computes both the minimum and the maximum of an array
63    * @param values an array of floating-point numbers
64    * @return a pair whose first element is the minimum and whose second element
65    * is the maximum
66    */
67   public static Pair minmax(double[] values)
68   {
69      double min = Double.POSITIVE_INFINITY;
70      double max = Double.NEGATIVE_INFINITY;
71      for (double v : values)
72      {
73         if (min > v) min = v;
74         if (max < v) max = v;
75      }
76      return new Pair(min, max);
77   }
78 }

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For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020