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| 8.9.19.Wrapper classes can be constructed by passing the value to the appropriate constructor. |
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public class MainClass {
public static void main(String[] argv) {
boolean primitiveBoolean = true;
Boolean wrappedBoolean = new Boolean(primitiveBoolean);
byte primitiveByte = 41;
Byte wrappedByte = new Byte(primitiveByte);
char primitiveChar = 'M';
Character wrappedChar = new Character(primitiveChar);
short primitiveShort = 31313;
Short wrappedShort = new Short(primitiveShort);
int primitiveInt = 12345678;
Integer wrappedInt = new Integer(primitiveInt);
long primitiveLong = 12345678987654321L;
Long wrappedLong = new Long(primitiveLong);
float primitiveFloat = 1.11f;
Float wrappedFloat = new Float(primitiveFloat);
double primitiveDouble = 1.11111111;
Double wrappedDouble = new Double(primitiveDouble);
}
}
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| 8.9.Wrapper classes | | 8.9.1. | Wrapper classes | | | | 8.9.2. | Wrapper classes and their corresponding primitive variables. | | | | 8.9.3. | Each Java primitive data type has a corresponding wrapper class. | | | | 8.9.4. | The Wrapper Constructors | | | | 8.9.5. | The Character class provides only one constructor, which takes a char as an argument | | | | 8.9.6. | The constructors for the Boolean wrapper take either a boolean value true or false, or a String. | | | | 8.9.7. | The valueOf() Methods | | | | 8.9.8. | Using Wrapper Conversion Utilities | | | | 8.9.9. | parseXxx() and valueOf() | | | | 8.9.10. | toString() | | | | 8.9.11. | Integer and Long provide a toString() method based on a radix. | | | | 8.9.12. | toXxxString() (Binar y, Hexadecimal, Octal) | | | | 8.9.13. | autoboxing, auto-unboxing, boxing, and unboxing. | | | | 8.9.14. | Assignment to wrapper object | | | | 8.9.15. | Each of the primitive data types has a corresponding wrapper class in the Java standard library. | | | | 8.9.16. | Integer.parseInt(): convert int to string | | | | 8.9.17. | Integer.valueOf(String s) returns Integer objects | | | | 8.9.18. | Integer.MAX_VALUE is the largest value and Integer.MIN_VALUE the smallest that an int primitive can contain. | | | | 8.9.19. | Wrapper classes can be constructed by passing the value to the appropriate constructor. | | | | 8.9.20. | Pass into the constructor a String that represents the value to be wrapped. | | | | 8.9.21. | The values wrapped inside two wrappers of the same type can be checked for equality | | | | 8.9.22. | After a value has been wrapped, you may eventually need to extract it. | | | | 8.9.23. | Sometime you need wrapper class | | | | 8.9.24. | Useful methods from wrapper class | | | | 8.9.25. | All wrapper classes except Character have a static method called valueOf(String s) | | | | 8.9.26. | static wrapper methods parseXXX() | | | | 8.9.27. | Boolean.getBoolean(), Integer.getInteger(), and Long.getLong(). | | | | 8.9.28. | All the wrapper classes provide toString() methods. | | | | 8.9.29. | Integer and Long classes provide toBinaryString(), toOctalString(), and toHexString() methods | | | | 8.9.30. | The values All wrapper classes wrap are immutable and Wrapper classes are final. | | |
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