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• Clearly comment subtle fixes.
• Clearly comment tricky classes and functions.
• If you have to choose between commenting code and writing wiki content, comment the code. Link from the wiki to the source file if it makes sense.
• Include the seven-digit bug numbers.
• Personal names are discouraged in the source code, which is a team product.

Macros

• You can almost always use an inline function or class instead of a macro. Use a macro only when you really need it.
• Templates may be preferable to multi-line macros. (There may be subtle performance effects with templates on some platforms; revert to macros if absolutely necessary.)
• For build features such as PRODUCT, use #ifdef PRODUCT for multiple-line inclusions or exclusions.
• For short inclusions or exclusions based on build features, use macros like PRODUCT_ONLY and NOT_PRODUCT. But avoid using them with multiple-line arguments, since debuggers do not handle that well.
• Use CATCH, THROW, etc. for HotSpot-specific exception processing.

Grouping

• Group related code together, so readers can concentrate on one section of one file.
• Avoid making functions too large, more than a screenful of text; split out chunks of logic into file-local classes or static functions if needed.
• If a class FooBar is going to be used in more than one place, put it a file named fooBar.hpp and fooBar.cpp. If the class is a sidekick to a more important class BazBat, it can go in bazBat.hpp.
• Put a member function FooBar::bang into the same file that defined FooBar, or its associated *.cpp file.

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• Conform new code to style conventions. Avoid unnecessary "esthetic" variations, which are distracting.
• Use the C++ RAII design pattern to manage bracketed critical sections. See class ResourceMark for an example.
• +Verbose is used to provide additional output for another flag, but does not enable output by itself.
• Do not use ints or pointers as booleans with &&, ||, if, while. Instead, compare explicitly != 0 or != NULL, etc. (See #8 above.)
• Use functions from globalDefinitions.hpp when performing bitwise operations on integers. Do not code directly as C operators, unless they are extremely simple. (Examples: round_to, is_power_of_2, exact_log2.)
• More suggestions on factoring.

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