如何更改存储在java中的内存位置的值

Question

String val="Hello";
//blocks of code

int c=val.hashCode();  //say i get 101 as memory location.

Say i don't know what is the "val" at mem location 101 .And i want to store val="abc" at this location. How can i use the memory location to append the val ? Is this possible in Java.

Answer 1

Java doesn't allow direct manipulation of memory locations. It is built as a layer between the user and the actual memory.

Not to mention that hashcode has nothing to do with the memory address.

Per @ValekHalfHeart's comment I did a quick search and appearantly there is an API available for unsafe operations (including changes to the the memory location). I have no experience with this, but it might look like a backdoor to do what you want.

Do note that Java is explicitly built to abstract all these things away from you. Trying to use them after all is abusing your tools.

Answer 2

The short answer to your question is "no". Java "protects" you from knowing (or caring) about the memory locations of objects, allocation, destruction, etc.

If you like that kind of thing, might I recommend you use C? It's a much maligned language - but it's great for that kind of "close to the silicon" programming. With all the perils that entails...