Java Library Online Library 2022 JDK is a set of JavaDevelopmentKit environment provided by SUN. It is the core of the whole Java, including Java compiler, Java running tool, Java document generation tool and Java packaging tool. After JDK is installed, a directory will be generated on the hard disk, which is called the installation directory of JDK.

"The library in java is an institution that collects, sorts out and collects books and materials for people to read and refer to. As early as 3000 BC, libraries appeared, which have the functions of preserving human cultural heritage, developing information resources and participating in social education.