RFR 8251203: Fix "no comment" warnings in java.base/java.lang and java/io

[Roger Riggs]

Please review the addition of comments to classes and fields to resolve
javadoc "no comment" warnings in the java.lang and java.io packages.
The comments are derived from the existing behavior and context.

Webrev:
    http://cr.openjdk.java.net/~rriggs/webrev-nocomment-8251203-1/

CSR:
     https://bugs.openjdk.java.net/browse/JDK-8252129

Issue:
     https://bugs.openjdk.java.net/browse/JDK-8251203

Thanks, Roger