关于java常量存储方式的问题，大家帮忙看一下

最近学习java，有个String的小问题请教一下大伙，大家帮忙看一下！
String str=new String("Hello");
System.out.prinln(str.length());//输出为5
本人查了一下String的源码，有如下几个构造方法：
public String(String original) {
int size = original.count;
char[] originalValue = original.value;
char[] v;
if (originalValue.length > size) {
// The array representing the String is bigger than the new
// String itself. Perhaps this constructor is being called
// in order to trim the baggage, so make a copy of the array.
int off = original.offset;
v = Arrays.copyOfRange(originalValue, off, off+size);
} else {
// The array representing the String is the same
// size as the String, so no point in making a copy.
v = originalValue;
}
this.offset = 0;
this.count = size;
this.value = v;
}


public String(char value[]) {
int size = value.length;
this.offset = 0;
this.count = size;
this.value = Arrays.copyOf(value, size);
}

public int length() {
return count;
}
对于str.length()，返回的是Count的值即字符串的长度，我想问的是对于new String("Hello")调用的是哪个构造方法，如果调用的是String(String original)，那么在这个函数中Hello的长度是怎么来的，编译器如何解释这部分，大虾们帮忙看一下！！！