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*EXP03:* In general, for any two objects, it is permissible to compare their elements provided that the class is a singleton. The use of static factory methods over constructors facilitates instance control which in turn limits the effective number of instances of an immutable class to one. As a result, for two objects {{a}} and {{b}}, {{a.equals(b)}} is {{true}} when {{a == b}} \[[Bloch 082008|AA. Java References#Bloch 08]\]. The {{String}} class does not meet these requirements and consequently, does not possess these characteristics.

\[[JLS 052005|AA. Java References#JLS 05]\] [Section 3.10.5, String Literals|http://java.sun.com/docs/books/jls/third_edition/html/lexical.html#3.10.5]
\[[FindBugs 082008|AA. Java References#FindBugs 08]\] ES: Comparison of String objects using == or \!=
\[[MITRE 092009|AA. Java References#MITRE 09]\] [CWE ID 595|http://cwe.mitre.org/data/definitions/595.html] "Incorrect Syntactic Object Comparison", [CWE ID 597|http://cwe.mitre.org/data/definitions/597.html] "Use of Wrong Operator in String Comparison"