Java Integer class
The Integer class wraps a primitive int type value in an object. Its object contains only a single field whose type is int.
Methods:
The java.lang.Integer class provides several different methods for converting an Integer to a String or vice versa. This class also provides other constants and methods which are useful when we are dealing with int.
Examples-
Example:1
| Methods | Description |
| bitCount() | It returns the number of one bits in two’s complement binary representation of the given int value. |
| byteintValue() | It returns the value of Integer as a byte. |
| compare() | It compares the two int values. |
| compareTo() | It compares two Integer objects numerically. |
| compareUnsigned() | It compares the two int values keeping the values unsigned. |
| decode() | It decodes a string into an Integer. |
| divideUnsigned() | It returns the unsigned quotient by dividing the first argument by the second. |
| doubleValue() | IT returns the value of Integer as a double. |
| equals() | It compares this object with the specified object. |
| floatValue() | It returns the float type value for the given Integer object. |
| getInteger() | It determines the int value of the system property for the specified name. |
| hashCode() | It returns the hash code for the specified Integer object. |
| highestOneBit() | It returns an int value with at most one single bit in the place of the highest order one-bit. |
| intValue() | It returns an int value for this Integer. |
| longValue() | It returns a long value for this Integer object |
| lowestOneBit() | It returns an int value with at most one single bit in the place of the lowest order one-bit. |
| max() | It returns the greater of the two int values. |
| min() | It returns the smaller of the two int values. |
| numberOfLeadingZeros(int i) | It returns the total number of zero bytes following the highest order one-bit in the two’s complement binary representation. |
| numberOfTrailingZeroes(int i) | It returns the total number of zero bytes following the lowest order one-bit in the two’s complement binary representation. |
| parseInt() | It parses the CharSequence or String argument as a specified signed int. |
| parseUnsignedInteger() | It parses the given CharSequence or String argument as an unsigned int. |
| remainderUnsigned() | It returns the unsigned remainder by dividing the first argument with the second argument. |
| reverse() | It returns the value obtained by the reversing the given order of bits in 2’s complement binary representation. |
| reverseBytes() | It returns the value obtained by the reversing the given order of bytes in 2’s complement representation. |
| rotateLeft() | It returns the value obtained by rotating the 2’s complement binary representation of the given int value by left and by the specified number of bits. |
| rotateRight() | It returns the value obtained by rotating the 2’s complement binary representation of the given int value by right and by the specified number of bits. |
| shortValue() | It returns the short type value for the given Integer object. |
| signum() | It returns the signum function for the given int value. |
| sum() | It adds the two specified int values and returns the same result as the + operator. |
| toBinaryString() | It returns the string representation for the given integer argument as an unsigned argument with base 2. |
| toHexString() | It returns the string representation for the given int argument as an unsigned argument with base 16. |
| toOctalString() | Returns the string representation for the given int argument as an unsigned argument with base 8. |
| toString() | It returns the string which represents the same value as of the given integer. |
| toUnsignedString() | It returns the string representation for the argument as an unsigned decimal value. |
| toUnsignedLong() | It converts the given int argument to long by an unsigned conversion. |
| valueOf() | It returns an int instance which represents the specified value. |
public class JavaIntegerExample1 {
static int i=1;
public static void main(String[] args) {
Integer val1 = 500 ;
Integer val2 = 127654 ;
Integer val3=127654;
// It compares two Integer objects numerically
int val = val1.compareTo(val2);
if (val>0) {
System.out.println(i++ + ". "+val1 + " is greater than " + val2);
}
else{
System.out.println(i++ + ". "+val2 + " is greater than " + val1);
}
//It is used check whether both int values are equal or not.
Boolean b1 = val3.equals(val2);
if (b1) {
System.out.println(i++ + ". "+val2 + " and " + val3 +" are equal
.");
}
else{
System.out.println(i++ + ". "+val1 + " and " + val2 +" are not equal
.
");
}
//returns the value of this Integer as a long
Long f3 = val2.longValue();
System.out.println(i++ + ". "+"Long value of "+val2+ " is : "+f3);
//Returns a string representation of the Integer’s object
String f4 = val2.toString();
System.out.println(i++ + ". "+"String value of "+val2+ " is : "+f4);
//It returns a double value for this Integer object
Double f5 = val1.doubleValue();
System.out.println(i++ + ". "+"Double value of "+val1+ " is : "+f5);
}
}
Output:
500 is greater than 12 12 and 12 are equal. Long value of 12 is : 12 String value of 12 is : 12 Double value of 500 is : 500.0Example:2
public class JavaIntegerExample2 {
static int i=1;
public static void main(String[] args) {
Integer val1 = 50 ;
Integer val2 = 607 ;
//compares the two specified int values
int val = Integer.compare(val1,val2);
if (val>0) {
System.out.println(i++ + ". "+val1 + " is greater than " + val2);
}
else{
System.out.println(i++ + ". "+val2 + " is greater than " + val1);
}
// returns the hash code of int value val1
int f1 = val1.hashCode();
System.out.println(i++ + ". "+"Hash code value of "+val1+ " is : "+f1);
//returns the value of this Integer as a Float
Float f2 = val2.floatValue();
System.out.println(i++ + ". "+"Float value of "+val2+ " is : "+f2);
//returns the value of this Integer as a Float
Integer f3 = val2.intValue();
System.out.println(i++ + ". "+"Integer value of "+val2+ " is : "+f3);
//decodes a String into a Integer
String str="123";
Integer f4 = Integer.decode(str);
System.out.println(i++ + ". "+"Decoded value of string value "+str+ " is
: "+f4);
}
}
Output:
607 is greater than 50 Hash code value of 50 is : 50 Float value of 607 is : 607.0 Integer value of 607 is : 607 Decoded value of string value 123 is : 123