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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