Covariance and contravariance might seem esoteric, but you'll need these concepts more than ever as the Java language evolves. Get started with type dependency in array types, generic types, and ...

Variables and primitive types Called primitive types, integral and floating point types are the simplest data types in Java. The following program illustrates the integral type, which can hold ...

We have only discussed a couple of the potential problems caused by bad data types. In general, it is best to assign your columns the data type (and length) that best matches the values in its domain.