Sun's published code conventions specify source formatting that is not supported by the built-in formatter.

http://java.sun.com/docs/codeconv/html/CodeConvTOC.doc.html

In particular the "wrapping" section http://java.sun.com/docs/codeconv/html/CodeConventions.doc3.html#248 clearly 
specifies that lines should break BEFORE and operator (for good reason), yet the built-in formatter breaks lines after 
operators.

E.g. Sun code conventions would break a line like this:
longName1 = longName2 * (longName3 + longName4 - longName5)
           + 4 * longname6;

But the NetBeans formatter would break the same line like this:
longName1 = longName2 * (longName3 + longName4 - longName5) +
           4 * longname6;

Since the operator is left dangling at the en of the line, where it still may need horizontal scrolling to become 
visible, it is less clear how the continuation line relates to the previous line.  Coding preferences aside, the 
published conventions should be supported.