How does Java decide when to import?

Question

Why doesn\'t Java need to import classes like Integer, String, etc. while it needs to import other classes?

Answer 1

every class in java is in a package and if no package is defined then it is understood as in default package. And at the top of the package is java.lang.* so we don't need to import it an require to import other classes.

Answer 2

java.lang is in-build, implicitly imported in java, does'nt need to be manually imported

Answer 3

As it contains very frequently used classes, they have made it optional to import just for your convenience

Answer 4

There is an implicit import of java.lang.*.

From the Java specification:

A compilation unit automatically has access to all types declared in its package and also automatically imports all of the public types declared in the predefined package java.lang.

Answer 5

Integer,String etc classes are present in package java.lang which is default imported.

Answer 6

Because, they belongs to java.lang.* package. And, it is implicitly import by the compiler. If you do, then it won't complain you.