How can be interpreted code even little efficient? (theoretical)
OK, first, I dont want any kind of flamewar here or anything like it. My bigger question is more theoretical, and will include few examples.

So, as I wrote, I cannot understand how can interpreted language be even little efficient. And since its modern, I will take Java as example.

Lets go back to days where there was no JIT compilers. Java has its virtual machine which is basically its hardware. You write code, than it compiled into bytecode for taking at least some job off the virtual machine, thats fine. But considering how complex even RISC instruction set can be in hardware, I cannot even think of way to do it at software emulated hardware.

I have no experience writing virtual machines, so I dont know how its done at most efficient level, but I cannot think of anything more efifcient than testing every instruction for match adn than do appropriate actions. You know, something like: `if(instruction=="something") { (do it) } else if(instruction=="something_diffrent"){ (do it) }`etc....

But this has to be terribly slow. And still, even there are articles that java was slow before JIT compilers, they still say that its not so slow. But for emulating it must take many clock cycles of real HW to perform one bytecode instruction.

And still, even entire platforms are based on java. For example, Android. And first verisons of Android had no JIT compiler. They were interpreted. But should not than be Android terribly slow? And yet it is not. I know, when you call some API function, from Android library, they are written in machine code, so they are efficient, so this helps a lot.

But imagine that you would write your own game engine from sratch, using API just for displaying images. You would need to do many array copy operations, many calculations which would be terribly slow when emulated.

And now some examples as I promised. Since I mainly work with MCUs, I found JVM for Atmel AVR MCU. Thay state that 8MHZ MCU can do 20K java optcodes per second. But since AVR can do most instructions in one or two cycles, lets say 6000000 instructions average. This gives us that JVM without JIT compiler is 300 times slower to machine code. So why become java so popular without JIT compiler? Isnt this too bad performance loss? I just cannot understand it. Thanks.
How can be interpreted code even little efficient? (theoretical)
===

OK, first, I dont want any kind of flamewar here or anything like it. My bigger question is more theoretical, and will include few examples.

So, as I wrote, I cannot understand how can interpreted language be even little efficient. And since its modern, I will take Java as example.

Lets go back to days where there was no JIT compilers. Java has its virtual machine which is basically its hardware. You write code, than it compiled into bytecode for taking at least some job off the virtual machine, thats fine. But considering how complex even RISC instruction set can be in hardware, I cannot even think of way to do it at software emulated hardware.

I have no experience writing virtual machines, so I dont know how its done at most efficient level, but I cannot think of anything more efifcient than testing every instruction for match adn than do appropriate actions. You know, something like: `if(instruction=="something") { (do it) } else if(instruction=="something_diffrent"){ (do it) }`etc....

But this has to be terribly slow. And still, even there are articles that java was slow before JIT compilers, they still say that its not so slow. But for emulating it must take many clock cycles of real HW to perform one bytecode instruction.

And still, even entire platforms are based on java. For example, Android. And first verisons of Android had no JIT compiler. They were interpreted. But should not than be Android terribly slow? And yet it is not. I know, when you call some API function, from Android library, they are written in machine code, so they are efficient, so this helps a lot.

But imagine that you would write your own game engine from sratch, using API just for displaying images. You would need to do many array copy operations, many calculations which would be terribly slow when emulated.

And now some examples as I promised. Since I mainly work with MCUs, I found JVM for Atmel AVR MCU. Thay state that 8MHZ MCU can do 20K java optcodes per second. But since AVR can do most instructions in one or two cycles, lets say 6000000 instructions average. This gives us that JVM without JIT compiler is 300 times slower to machine code. So why become java so popular without JIT compiler? Isnt this too bad performance loss? I just cannot understand it. Thanks.