 # Java Math nextUp()

That is, if the argument is 6.7, then the adjacent number of 6.7 in direction of positive infinity is 6.700000000000001.

The syntax of the `nextUp()` method is:

``Math.nextUp(start)``

Note: The `nextUp()` method is a static method. Hence, we can call the method directly using the class name `Math`.

## nextUp() Parameters

• start - starting number whose adjacent number is returned

Note: The data type of start can be either float or double.

## nextUp() Return Values

• returns the number adjacent to start towards positive infinity
• returns NaN if start is NaN
• returns positive infinity if start is positive infinity

Note: The `nextUp()` method is equivalent to the Math.nextAfter(start, Double.POSITIVE_INFINITY).

## Example: Java Math.nextUp()

``````class Main {
public static void main(String[] args) {

// float arguments
float start1 = 7.9f;
System.out.println(Math.nextUp(start1));  // 7.9000006

// double arguments
double start2 = 7.9;
System.out.println(Math.nextUp(start2));  // 7.900000000000001

// with positive infinity
double infinity = Double.POSITIVE_INFINITY;
System.out.println(infinity);            // Infinity

// with NaN
double nan = Math.sqrt(-5);
System.out.println(Math.nextUp(nan));    // NaN

}
}``````

Here, we have used the Java Math.sqrt(-5) method to calculate the square root of -5. Since, the square root of a negative number is not a number, `Math.nextUp(nan)` returns NaN.

The `Double.POSITIVE_INFINITY` is a field of `Double` class that allows us to implement infinity in a program.