It’s almost always a mistake to compare two instances of java.lang.String or boxed types like java.lang.Integer using
reference equality == or !=, because it is not comparing actual value but locations in memory.
Noncompliant code example
String firstName = getFirstName(); // String overrides equals
String lastName = getLastName();
if (firstName == lastName) { ... }; // Non-compliant; false even if the strings have the same value
Compliant solution
String firstName = getFirstName();
String lastName = getLastName();
if (firstName != null && firstName.equals(lastName)) { ... };
