Integer highestOneBit() Method in Java

The Integer.highestOneBit() method of java.lang returns an integer value with at most a single one-bit which is in the position of the highest-order (ie.leftmost) one-bit for the given int value. If the specified value has no one-bits in its two’s complement binary representation then it returns zero, simply if it is equal to zero.
Syntax:

public static int highestOneBit(int a)

Parameters: The method takes one parameter a of integer type that refers to the value whose highest order bit is to be returned or on which the operation is to be performed.
Returns : The method can return two types of values:  

• Returns an integer value with a single 1-bit, in the position of the highest-order one-bit in the specified value
• Returns zero if the specified value is equal to zero.

Examples:

Input: 19
Output: Highest one bit of the given integer is = 16

Input: -9
Output: Highest one bit of the given integer is = -2147483648

Explanation:
Consider any integer a = 19
Binary Representation = 0001 0011
Highest bit(at 4) i.e.0001 0000
so result = 2^4=16

Below programs illustrate the Java.lang.Integer.highestOneBit() Method. 
Program 1: For a positive number. 

java

// Java program to illustrate the
// Java.lang.Integer.highestOneBit() Method
import java.lang.*;

public class HighestOneBit {

    public static void main(String[] args)
    {

        int a = 29;
        System.out.println("Number is = " + a);

        // returns an int value with at most a single one-bit, in the position
        // of the highest-order or the leftmost one-bit in the specified int value
        System.out.print("Highest one bit of the given integer is = ");
        System.out.println(Integer.highestOneBit(a));
        a = 44;
        System.out.println("Number is = " + a);
        System.out.print("Highest one bit of the given integer is = ");
        System.out.println(Integer.highestOneBit(a));
    }
}

Output:

Number is = 29
Highest one bit of the given integer is = 16
Number is = 44
Highest one bit of the given integer is = 32

Program 2: For a negative number. 

java

// Java program to illustrate the
// Java.lang.Integer.highestOneBit() Method
import java.lang.*;

public class HighestOneBit {

    public static void main(String[] args)
    {

        int a = -9;
        System.out.println("Number is = " + a);

        // returns an int value with at most a single one-bit, in the position
        // of the highest-order or the leftmost one-bit in the specified int value
        System.out.print("Highest one bit of the given integer is = ");
        System.out.println(Integer.highestOneBit(a));
    }
}

Output:

Number is = -9
Highest one bit of the given integer is = -2147483648

Program 3: For a decimal value. 
Note:It returns an error message when a decimal value is passed as an argument because of incompatible types. 

java

// Java program to illustrate the
// Java.lang.Integer.highestOneBit() Method
import java.lang.*;

public class HighestOneBit {

    public static void main(String[] args)
    {

        int a = 84.22;
        System.out.println("Number is = " + a);

        // decimal value 84.22 is passed here
        System.out.print("Highest one bit of the given integer is = ");
        System.out.println(Integer.highestOneBit(a));
    }
}

Output:

prog.java:9: error: incompatible types: possible lossy conversion from double to int
    int a = 84.22;
            ^
1 error

Program 4: For a String. 
Note:It returns an error message when a String is passed as an argument because of incompatible types. 

java

// Java program to illustrate the
// Java.lang.Integer.highestOneBit() Method
import java.lang.*;

public class HighestOneBit {

    public static void main(String[] args)
    {

        int a = "34";
        System.out.println("Number is = " + a);

        // decimal value 84.22 is passed here
        System.out.print("Highest one bit of the given integer is = ");
        System.out.println(Integer.highestOneBit(a));
    }
}

Output:

prog.java:9: error: incompatible types: String cannot be converted to int
    int a = "34";
            ^
1 error