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Java Built-In Libraries Every Developer Must Know
Don’t Reinvent the Wheel
Published in
5 min readJan 3, 2025
Below are some built-in libraries with code examples and you can see how powerful and convenient the standard libraries are. Instead of reinventing the wheel, let Java’s built-in tools do the heavy lifting.
1. Using Math
for Common Calculations
The Math
class offers a variety of common mathematical functions (absolute value, power, roots, rounding, trigonometric functions, etc.) which can save you from writing your own.
public class MathExample {
public static void main(String[] args) {
double num = -8.25;
// Absolute value
System.out.println("Absolute Value: " + Math.abs(num));
// Power
System.out.println("2 to the power 3: " + Math.pow(2, 3));
// Square root
System.out.println("Square root of 16: " + Math.sqrt(16));
// Rounding
System.out.println("Rounded value of -8.25: " + Math.round(num));
}
}
2. Random Number Generation with Random
Java’s Random
class quickly lets you create random values for simulations, games, testing scenarios, and more.
import java.util.Random;
public class RandomExample {…