A JIT has access to dynamic runtime information whereas a standard compiler doesn't and can make better optimizations like inlining functions that are used frequently.
This is in contrast to a traditional compiler that compiles all the code to machine language before the program is first run..
Compiler : Compiler's job is to compile the code which is written in any language and create byte code to execute in machine.
Each language have their own compilers.
JVM : JVM is java virtual machine and its contains the compiler for java language and create byte code which will be executed on any plateform..
JIT is the tool which can transform bytecode to the binary code. javac is the tool which can transform code to the Java bytecode..
The typical compilation process (non-JIT or Ahead-of-Time compilation) translates a high-level programming language to machine code at compile time.
During execution of the program (runtime), machine code is fixed.
Just-in-Time is a technique to generate/re-generate machine code at runtime..
JIT code generally offers far better performance than interpreters.
In addition, it can in some cases offer better performance than static compilation, as many optimizations are only feasible at run-time: The compilation can be optimized to the targeted CPU and the operating system model where the application runs..
Pre-JIT Compiler (Compiles entire code into native code completely) Econo JIT Compiler (Compiles code part by part freeing when required) Normal JIT Compiler (Compiles only that part of code when called and places in cache..
Static Java compilers can perform resource intensive optimization before the execution of the program.
In contrast, JIT compilers must perform analysis at execution time, thus are limited to simple optimizations that can be done without a large impact on the combined compile and execute time..
If the behavior of the application changes while it is running, the runtime environment can recompile the code.
Some of the disadvantages include:
Within the family of JIT compilers, there are still many differences as to when exactly they compile, how often, and at what granularity.
For example, some JIT compilers compile code as soon as it is loaded for the first time.
Some JIT compilers wait until the code needs to be executed.
Some JIT compilers compile code only once.
Some may choose to .
An interpreter for language X is a program (or a machine, or just some kind of mechanism in general) that executes any program p written in language X such that it performs the effects and evaluates the results as prescribed by the specification of X.
CPUs are usually interpreters for their respective instructions sets, although modern high-perform.
An interpreter directly executes the source code.
JIT compilation attempts to use the benefits of both.
While the interpreted program is being run, the JIT compiler determines the most frequently used code and compiles it to machine code.
Depending on the compiler, this can be done on a method or smaller section of code.
The JVM emulates the expected behaviour for each instruction.
Interpreters converts bytecode into corresponding native machine code for execution, bytecodes are not directly executing.
A JIT Compiler translates byte code into machine code and then execute the machine code.
Static compilation converts the code into a language for a specific platform.
An interpreter directly executes the source code.
JIT compilation attempts to use the benefits of both.
While the interpreted program is being run, the JIT compiler determines the most frequently used code and compiles it to machine code.
