When the call to a function doesn't have any side effects, what is the point of making the call if the results are ignored? In such case, either the function call is useless and should be dropped or the source code doesn't behave as expected.
To prevent generating any false-positives, this rule triggers an issue only on the following predefined list of immutable classes in the Java API :
java.lang.String java.lang.Boolean java.lang.Integer java.lang.Double java.lang.Float java.lang.Byte java.lang.Character java.lang.Short java.lang.StackTraceElement java.time.DayOfWeek java.time.Duration java.time.Instant java.time.LocalDate java.time.LocalDateTime java.time.LocalTime java.time.Month java.time.MonthDay java.time.OffsetDateTime java.time.OffsetTime java.time.Period java.time.Year java.time.YearMonth java.time.ZonedDateTime java.math.BigInteger java.math.BigDecimal java.util.Optional
public void handle(String command){
command.toLowerCase(); // Noncompliant; result of method thrown away
...
}
public void handle(String command){
String formattedCommand = command.toLowerCase();
...
}
This rule will not raise an issue when both these conditions are met:
try block with an associated catch clause. String.getBytes(Charset).
private boolean textIsInteger(String textToCheck) {
try {
Integer.parseInt(textToCheck, 10); // OK
return true;
} catch (NumberFormatException ignored) {
return false;
}
}