It is not possible to write a Java program without using the standard libraries, also called Java Class Library (JCL). That is why a solid familiarity with such libraries is as vital for successful programming as the knowledge of the language itself.
There are also non-standard libraries, called external libraries or third-party libraries because they are not included in Java Development Kit (JDK) distribution. Some of them have long become a permanent fixture of any programmer toolkit.
To keep track of all the functionality available in these libraries is not easy. That is because an Integrated Development Environment (IDE) gives you a hint about the language possibilities, but it cannot advise about the functionality of a package not imported yet. The only package that is imported automatically is java.lang.
This purpose of this chapter is...