@Test public void defaultMethod() throws Exception { Formula formula = new Formula() { @Override public double calculate(int a) { return sqrt(a * 100); } }; assert formula.calculate(100) == 100.0; assert formula.sqrt(16) == 4.0; }
public static void main(String[] args) { Formula formula1 = new Formula() { @Override public double calculate(int a) { return sqrt(a * 100); } }; formula1.calculate(100); // 100.0 formula1.sqrt(-23); // 0.0 Formula.positive(-4); // 0.0 // Formula formula2 = (a) -> sqrt( a * 100); }