How can I represent a range in Java?

Apache Commons Lang has a Range class for doing arbitrary ranges. Guava Range has similar API. If you are just wanting to check if a number fits into a long value or an int value, you could try using it through BigDecimal. There are methods for longValueExact and intValueExact that throw exceptions if the value is too big for those precisions.

What is the difference between a null array and an empty array?

Technically speaking, there’s no such thing as a null array; but since arrays are objects, array types are reference types (that is: array variables just hold references to arrays), and this means that an array variable can be null rather than actually pointing to an array: An empty array is an array of length zero; it has no elements: (and can never have elements, … Read more

org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when ‘hibernate.dialect’ not set

First remove all of your configuration Spring Boot will start it for you. Make sure you have an application.properties in your classpath and add the following properties. If you really need access to a SessionFactory and that is basically for the same datasource, then you can do the following (which is also documented here although for XML, not JavaConfig). That way … Read more

What is Java String interning?

http://docs.oracle.com/javase/7/docs/api/java/lang/String.html#intern() Basically doing String.intern() on a series of strings will ensure that all strings having same contents share same memory. So if you have list of names where ‘john’ appears 1000 times, by interning you ensure only one ‘john’ is actually allocated memory. This can be useful to reduce memory requirements of your program. But … Read more

What is Java String interning?

http://docs.oracle.com/javase/7/docs/api/java/lang/String.html#intern() Basically doing String.intern() on a series of strings will ensure that all strings having same contents share same memory. So if you have list of names where ‘john’ appears 1000 times, by interning you ensure only one ‘john’ is actually allocated memory. This can be useful to reduce memory requirements of your program. But … Read more

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)