A DESCRIPTION OF THE PROBLEM : The two words are confused in the following: "The first principal is that most users want the standard ISO calendar system. As such, the main classes are ISO-only. The second principal is that..." 'Principal' means first or primary as an adjective, and refers to a person as a noun, while 'principle' means rule or guideline, which is the intended meaning in the lines quoted above. see http://www.oxforddictionaries.com/us/words/principal-or-principle EXPECTED VERSUS ACTUAL BEHAVIOR : EXPECTED - "The first principle is that most users want the standard ISO calendar system. As such, the main classes are ISO-only. The second principle is that..." URL OF FAULTY DOCUMENTATION : http://docs.oracle.com/javase/8/docs/api/java/time/package-summary.html#package.description