Programmer's Guide to Java™ Certification, A: A Comprehensive Primer, Second Edition

2. Language Fundamentals

2.1	(c) 52pickup is not a legal identifier. The first character of an identifier cannot be a digit.
2.2	(e) In Java, the identifiers delete, thrown, exit, unsigned, and next are not keywords. Java has a goto keyword, but it is reserved and not currently used.
2.3	(b) It is a completely valid comment. Comments do not nest. Everything from the start marker of a comment block (/*) until the first occurrence of the end marker of the comment block (*/) is ignored by the compiler.

2.4	(a) and (d) String is a class, and "hello" and "t" denote String objects. Java only has the following primitive data types: boolean, byte, short, char, int, long, float, and double.
2.5	(a), (c), and (e) Type (a) is a boolean data type, while types ...