1) Because in an object oriented language "evereything" is supposed to be an "object". Of course primitives are an exception to this rule in Java, for efficiency reasons.
2) Sun provides LOTS of libraries that we can use. The java.lang package is just ONE of these provided in the jre. They did this because they are REALLY good at coding java
, and they wanted some control over the way the basic functionality of the language grew and was implemented.