JDK1.4, 1.5 的 String Class 代码如下
[code]
public final class String
implements Java.io.Serializable, Comparable<String>, CharSequence
{
/** The value is used for character storage. */
private final char value[];
/** The offset is the first index of the storage that is used. */
private final int offset;
/** The count is the number of characters in the String. */
private final int count;
[/code]
[code]
/**
* Initializes a newly created <code>String</code> object so that it
* represents the same sequence of characters as the argument; in other
* Words, the newly created string is a copy of the argument string. Unless
* an eXPlicit copy of <code>original</code> is needed, use of this
* constrUCtor is unnecessary since Strings are immutable.
*
* @param original a <code>String</code>.
*/
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.
v = new char[size];
System.arraycopy(originalValue, original.offset, v, 0, 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;
}
[/code]
从这段构造函数中，我们可以看出，不同Reference的String之间有可能共享相同的 char[]。
