标注：
1. String类重写了java.lang.Object类的euqals()方法，当使用该方法进行相等性判断时，比较的是两个字符串的内容是否相等。通常，我们使用java.lang.String类的public boolean equals(Object object)方法。
2. 对于基本数据类型，“==”比较的是两个变量的字面值。相等则返回true，否则返回false。
3. 对于引用数据类型，“==”比较其左右两边对象的地址值是否一致。
4. 从Java编程规范可以看出，对于采用字面值方式或字面值相加的方式赋值，属于编译期行为，只有“==”两边都属于编译期行为且内容相同，比较结果就为真。
5. 采用“对象+字面值”的方式赋值，属于运行期行为，即使比较的两个对象内容相同，比较结果也为false。
package testPackage;class Test {public static void main(String[] args) {String hello = "Hello", lo = "lo";System.out.print((hello == "Hello") + " ");System.out.print((Other.hello == hello) + " ");System.out.print((other.Other.hello == hello) + " ");System.out.print((hello == ("Hel"+"lo")) + " ");System.out.print((hello == ("Hel"+lo)) + " ");System.out.println(hello == ("Hel"+lo).intern());}}class Other { static String hello = "Hello"; }and the compilation unit:package other;public class Other { static String hello = "Hello"; }produces the output:true true true true false trueThis example illustrates six points:Literal strings within the same class (§8) in the same package (§7) represent references to the same String object (§4.3.1). Literal strings within different classes in the same package represent references to the same String object. Literal strings within different classes in different packages likewise represent references to the same String object. Strings computed by constant expressions (§15.28) are computed at compile time and then treated as if they were literals. Strings computed at run time are newly created and therefore distinct. The result of explicitly interning a computed string is the same string as any pre-existing literal string with the same contents.
