The else part of an if-else statement is optional. If it is missing, we have an if statement, which allows us to execute a certain part of code if a condition is satisfied (and do nothing otherwise).
First, the condition is evaluated. If the result of the evaluation is the value true, the then-statement is executed, and the execution continues with the statement immediately following the if statement. Otherwise, the execution continues directly with the statement following the if statement.
boolean found; ... if (!found) System.out.println("element not found");
When this if statement is executed, the string "element not found" is printed on the output channel, provided the value of the boolean variable found is false.