java lang Integer Class | Integer class methods in Java
java.lang.Integer Class
Integer Class in Java
The Integer class wraps the value of primitive data type int into Integer object. An object of type Integer contains a single field whose type is int. In other words the wrapper classes create objects for primitive data types. The wrapper classes are Boolean, Byte, Character, Short, Integer, Float, Long and Double.
Java Integer Methods or Integer class methods in Java
Java Integer class or Java wrapper class Integer provides several useful methods for converting a int to a String and a String to a int, as well as other constants and methods dealing with int. The various Java Integer methods are as follows :
java.lang.Integer Class Example
/* Java Integer Class Example Save with file name IntegerExample.java */ public class IntegerExample { public static void main(String args[]) { // JAVA INTEGER DECLARATION Integer b; // MEMORY ALLOCATION FOR JAVA INTEGER b = new Integer(101); // JAVA INTEGER CLASS OUTPUT System.out.println("Java Integer Class Example"); // RETURNS byte PRIMITIVE DATA TYPE System.out.println("byte Value is : "+ b.byteValue()); // RETURNS short PRIMITIVE DATA TYPE System.out.println("short Value is : "+ b.shortValue()); // RETURNS double PRIMITIVE DATA TYPE System.out.println("double Value is : "+ b.doubleValue()); // RETURNS float PRIMITIVE DATA TYPE System.out.println("float Value is : "+ b.floatValue()); // RETURNS int PRIMITIVE DATA TYPE System.out.println("int Value is : "+ b.intValue()); // RETURNS long PRIMITIVE DATA TYPE System.out.println("long Value is : "+ b.longValue()); } }
java.lang.Integer Class Example 2
/* Java Integer Class Example 2 Save with file name IntegerExample2.java */ public class IntegerExample2 { public static void main(String args[]) { // JAVA INTEGER DECLARATION Integer b, b2; // MEMORY ALLOCATION FOR JAVA INTEGER b = new Integer(101); b2 = new Integer("102"); // JAVA INTEGER CLASS OUTPUT System.out.println("Java Integer Class Example 2"); System.out.println("b Value is : "+ b.intValue()); System.out.println("b2 Value is : "+ b2.intValue()); System.out.println("b compareTo b2 : "+ b.compareTo(b2)); System.out.println("b equals b2 : "+ b.equals(b2)); } }
Following Java Integer class example you can learn how to use static methods of Java Integer Class. If you use static methods you need not to create the class instance. You can call static methods using the class name as reference.
java.lang.Integer Class Example 3
/* Java Integer Class Example 3 Save with file name IntegerExample3.java */ public class IntegerExample3 { public static void main(String args[]) { // INTEGER CLASS STATIC METHODS USAGE System.out.println("Java Integer Class Example 3"); // RETURN Java Integer OBJECT WITH THE SPECIFIED PRIMITIVE int DATA TYPE System.out.println("valueOf : "+ Integer.valueOf(101)); // RETURN Integer OBJECT WITH THE SPECIFIED // PRIMITIVE int DATA TYPE AS String System.out.println("valueOf : "+ Integer.valueOf("103")); // RETURN PRIMITIVE int DATA TYPE WITH THE SPECIFIED // PRIMITIVE int DATA TYPE AS String System.out.println("parseInt : "+ Integer.parseInt("105")); } }