[Java] Why i can use the class IntStream even the package java.util.stream not loaded ?

Fred.W.

355

When i used Java 8 stream API, for example, to get max of 3 int number. I tried to execute this at OJ:

IntStream.of(1, 2, 3]).max().getAsInt();

As the official document indicates, the class IntStream is from the package java.util.stream.
Just for curiosity, i listed all loaded packages:

Package[] ps = Package.getPackages();
Arrays.sort(ps, (p1, p2) -> p1.getName().compareTo(p2.getName()));
for (Package p : ps) {
  System.out.println(p.getName());
}

I got a list which i trust it is of all the loaded packages:

com.eclipsesource.json
com.sun.management
java.io
java.lang
java.lang.annotation
java.lang.invoke
java.lang.management
java.lang.ref
java.lang.reflect
java.net
java.nio
java.nio.charset
java.nio.charset.spi
java.nio.file
java.security
java.security.cert
java.util
java.util.concurrent
java.util.concurrent.atomic
java.util.concurrent.locks
java.util.function
java.util.jar
java.util.regex
java.util.zip
sun.launcher
sun.management
sun.misc
sun.net.util
sun.net.www
sun.net.www.protocol.file
sun.net.www.protocol.jar
sun.nio
sun.nio.ch
sun.nio.cs
sun.reflect
sun.reflect.annotation
sun.reflect.generics.repository
sun.reflect.misc
sun.security.action
sun.security.provider
sun.security.util
sun.usagetracker
sun.util
sun.util.locale

But java.util.stream didn't appear ! So that's my question: why i can used class IntStream even the package java.util.stream is not loaded ?

For more question, i checked the IntStream from which package:

System.out.println(IntStream.of(0).getClass().getPackage());

And i get this:

package java.util.stream, Java Platform API Specification, version 1.8

Could someone more familiar to java explain this to me ? i will appreciate it.

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