How can I speed up Java (running in windows xp)?

Browsers with JIT compilers include the Win32 and Mac versions of Netscape Navigator 3.0 and Internet Explorer 3.0. Standalone JIT compilers are also available from (at least):

* Asymetrix (commercial: for Win32).

* DEC (free: for Digital Unix)

* HP (free: for HP-UX).

* Kaffe (free: for x86, Sparc, Alpha, and M68k CPUs).

* Microsoft (free: for Win32).

* SGI (commercial: for Irix).

* Sun (free: for Win32 and Solaris).

* Symantec (commercial: for Win32 and MacOS).

Exploiting multiprocessors:

If you have a multiprocessor and a Java VM that can spread threads across processors (and currently these are big ifs), you can improve performance by multithreading, either manually or through the use of a restructuring compiler such as JAVAR.

Native methods:

If you're don't care about cross-platform portability, native methods will get you the speed of raw C (or Fortran, or C++, or...). Fallback code lets your program continue even if native methods aren't available.

Translation into C:

There are currently four freely-available tools to translate Java into C: j2c from Japan, JCC from Nik Shaylor, Toba (formerly Juice) from Arizona, and Harissa (formally Salsa) from France. Toba and Harissa are both products of active research groups.

Graphics:

Use clipping to reduce the amount of work done in repaint(), double buffering to improve perceived speed, and image strips or compression to speed up downloading times. Animation in Java Applets from JavaWorld and Performing Animation from Sun are two good tutorials. Remember to use high-level primitives; it's much faster to call drawPolygon() on a bunch of points than looping with drawLine() (tip from Jean-Marc Lugrin). And if you have to draw a single pixel drawLine (x,y,x,y) may be faster than fillRect (x,y,1,1) .