Where is java lang package

As mentioned in the beginning of this guide that we have two types of packages in java. 1) User defined package: The package we create is called user-defined package. 2) Built-in package: The already defined package like java.io.

There are seven types of classes in Java: Static Class. Final Class. Abstract Class.

There are 5,000 or so classes built-in to Java, and programmers have written hundreds of thousands if not millions of their own.