A standard C-style comment that begins with /* and
continues until the next */. As in most
implementations of C, this style of
comment cannot be nested.
A C++-style comment that begins with // and
continues until the end of the line.
A special "doc comment" that begins with /** and
continues until the next */. These comments may not
be nested. Doc comments are specially processed by the
javadoc program to produce simple online documentation
from the Java source code. See Chapter 13, Java Syntax for
more information on the doc comment syntax, and Chapter 16, JDK Tools for more information on the javadoc
Since C-style comments do not nest, it is a good idea to use
C++-style // comments for most of your short comments
within method bodies. This allows you to use /* */
comments to comment out large blocks of code when you need
to do that during development. This is especially important
because, as you will see, Java does not support a
preprocessor that allows you to use #if 0 to
comment out a block.