Although it is part of the java.util.concurrent package, the TimeUnit enum is useful in many contexts outside of concurrency .

JPA and Hibernate enum mapping The Java enum, introduced in Java 5, will map to the underlying database without any intervention. The JPA framework, be it Hibernate or Toplink or DataNucleus, will ...

More than once, I have seen code such as the following (without the comments I have added to point out flaws), in which a well-intentioned Java developer has ensured that their favorite Enum ...