The native types are not Objects. They are probably implemented somewhere in the JVM code (Native code).
There is usually a lot of debate whether the primitive type should be Objects or native. Making them Object is a overhead that the Java team decided to avoid. Instead the provided the wrapper class for each of the native types - that could be used with say Collections that did not support native types (autoboxing changes these rules a bit ).
So if you looking for where the 'int' 'float' are implemented you might have to go look at the JVM code (Actually i am not 100% on this.)