We can create more complex conditional structures by creating nested conditional statements, which is created by placing conditional statements inside other conditional statements:

if (outer condition) {
  if (nested condition) {
    Instruction to execute if both conditions are true
  }
}

When we implement nested conditional statements, the outer statement is evaluated first. If the outer condition is true, then the inner, nested statement is evaluated.

Let’s create a program that helps us decide what to wear based on the weather:

int temp = 45;
boolean raining = true;

if (temp < 60) {
  System.out.println("Wear a jacket!");
  if (raining == true) {
    System.out.println("Bring your umbrella.");
  } else {
    System.out.println("Leave your umbrella home.");
  }
}

In the code snippet above, our compiler will check the condition in the first if-then statement: temp < 60. Since temp has a value of 45, this condition is true; therefore, our program will print Wear a jacket!.

Then, we’ll evaluate the condition of the nested if-then statement: raining == true. This condition is also true, so Bring your umbrella is also printed to the screen.

Note that, if the first condition was false, the nested condition would not be evaluated.