What methods can you use to verify the fulfillment of conditions in code?

In Java, conditional statements if, else if, else, and switch are commonly used to check conditions in code. Logical operators (&&, ||, !) can also be used to combine conditions.

Example:

int age = 20;
if (age >= 18) {
    System.out.println("Adult");
} else {
    System.out.println("Minor");
}

Additionally, assertions are used in tests to verify conditions, for example with JUnit:

assertTrue(age >= 18);