Predefined libraries in Java

Java's strongest plus is it offers many pre-defined package libraries(class and interfaces) which can be used by developers for efficient coding.

Developers can use these libraries to easily convert their creative ideas to application form.

These predefined package libraries are bundled in the form of JAR's and are kept in lib folder of JDK(eg. C:\Program Files\Java\jdk1.8.0_77\lib ) or JRE root directory.

We can directly import any class or interface of library in our program if PATH variables or environmental variables are set correctly pointing to JDK.

You can refer Packages in Java to know how to import a class or interface of a package.

Important classes inside these libraries