Some methods contain a Compiled Code?

Question

From going to the source of some classes I saw some methods contain a compiled code, they are looks like this before expanding:

public void someMethod(){

Answer 1

Compiled code just means that the IDE doesn't have the source available to it (but the code is written in Java). The sun.* classes typically don't make their source available because they have a non-public API. This shouldn't be confused with native code, which can be written in C/C++ and called through JNI/JNA.