“带有char的字符串：”+'c'比带有char的字符串更好或更差：“+ c”？

Question

A small question, but one I'm genuinely curious about.

Is there anything inherently better or worse with

"a string with a char: " + 'x'

compared to

"a string with a char: " + "x"

?

They both work, but I am wondering if either has any performance or efficiency implications--minor as they may be.

Thanks.

Answer 1

public void test(){ 
    String str1 = "appl" + 'e';
    String str2 = "banan" + "a";
}

No change in byte code:

public void test();
    Code:
       0: ldc           #2                  // String apple
       2: astore_1      
       3: ldc           #3                  // String banana
       5: astore_2      
       6: return

I should mention that if you put the concatenation in a loop then StringBuilder will be used for both. That's all.

Answer 2

I am very sure that they will both generate the same efficient bytecode. Compilers are clever

So if there would be a difference (which I am not sure of), the compiler will erase it