Example 1: Java Program to calculate the method execution time
class Main {
// create a method
public void display() {
System.out.println("Calculating Method execution time:");
}
// main method
public static void main(String[] args) {
// create an object of the Main class
Main obj = new Main();
// get the start time
long start = System.nanoTime();
// call the method
obj.display();
// get the end time
long end = System.nanoTime();
// execution time
long execution = end - start;
System.out.println("Execution time: " + execution + " nanoseconds");
}
}
Output
Calculating Method execution time: Execution time: 656100 nanoseconds
In the above example, we have created a method named display(). The method prints a statement to the console. The program calculates the execution time of the method display().
Here, we have used the method nanoTime() of the System class. The nanoTime() method returns the current value of the running JVM in nanoseconds.
Example 2: Calculate the execution time of Recursive method
class Main {
// create a recursive method
public int factorial( int n ) {
if (n != 0) // termination condition
return n * factorial(n-1); // recursive call
else
return 1;
}
// main method
public static void main(String[] args) {
// create object of Main class
Main obj = new Main();
// get the start time
long start = System.nanoTime();
// call the method
obj.factorial(128);
// get the end time
long end = System.nanoTime();
// execution time in seconds
long execution = (end - start);
System.out.println("Execution time of Recursive Method is");
System.out.println(execution + " nanoseconds");
}
}
Output
Execution time of Recursive Method is 18600 nanoseconds
In the above example, we are calculating the execution time of recursive method named factorial().
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