Java and Just-in-time Compiler
l gPortableh languages e.g., Java
Does not compile directly to CPU native code
Interpretive execution of common bytecodes on
JVMs (Java VM)
Speed problem i1/10 ` 1/100 vs. optim. native code)
l Just-In-Time compiler to the rescue
Rather old idea: Smalltalk, etc.
Compile bytecode into native code at runtime
1/2 ` 1/10 vs. optim. native code
l Sun, MS, IBM, Symantec, Fujitsu, etc.,
vigorously developing gthe besth Java JIT. (e.g.,
HotSpotj