Java 7 for Absolute Beginners

CHAPTER 3 ■ DATA TYPES

Listing 3-4. String with escape sequence

String errorMessage = "The whatsit didn't work!\nCheck the doohickey.";
System.out.println(errorMessage);

That code snippet produces the output in Listing 3-5.

Listing 3-5. Newline output

The whatsit didn't work!
Check the doohickey.

Wrapper Classes

Each of the primitives (remember, String is an object rather than a primitive) has a corresponding class
that provides several useful abilities that are otherwise unavailable to a primitive. You can think of the
wrapper classes as each being a package of useful abilities wrapped around a primitive of the
corresponding type. Table 3-4 shows the corresponding class for each primitive:

Table 3-4. Wrapper classes

Primitive Class

byte Byte

short Short

int Integer

long Long

float Float

double Double

boolean Boolean

char Character

The most commonly used methods of those classes are the various parse, Value, and valueOf
methods, because those methods let you turn a String into a primitive. Each class also supports
toString methods to turn primitives into String objects. Listing 3-6 shows what you can do with an int
primitive.