Include all error-condition checking in blocks guarded by
if
statements.
Avoid throwing exceptions in the normal code path of your application.
Investigate whether a try-catch in the bottleneck
imposes any extra cost.
Use instanceof
instead of making speculative class casts in a
try-catch block.
Consider throwing exceptions without generating a stack trace by
reusing a previously created instance.
Include any exceptions generated during the normal flow of the
program when running performance tests.
Assertions add overhead even when
disabled, though an optimizing JIT compiler can eliminate the
overhead (only HotSpot server mode succeeded in 1.4.0).
Beware of adding assertions to quick, frequently called methods.
Minimize casting.
Avoid casts by creating and using type-specific collection classes.
Use temporary variables of the cast type, instead of repeatedly
casting.
Type variables as precisely as possible.
Use local variables rather than
instance or static variables for faster manipulation.
Use temporary variables to manipulate instance variables, static
variables, and array elements.
Use ints in preference to any other data type.
Avoid long and double instance
or static variables.
Use primitive data types instead of objects for temporary variables.
Consider accessing instance variables directly rather than through
accessor methods. (But note that this breaks encapsulation.)
Add extra method parameters when that would allow a method to avoid
additional method calls.
