问题
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How Does the toString(), ==, equals() object methods work differently or similarly on reference and primitive types?
I am trying to understand the difference between == and equals to operator in Java. e.g. == will check if it is the same object while equals will compare the value of the object ... Then why do we use == for comparing primitive data types like int. Because if I have
int i =7; //and
int j = 6.
They are not the same object and not the same memory address in stack. Or does the == behaves differently for primitives comparison.??
回答1:
Actually, == behaves identically for all variables: it tests whether the values of those variables are equal. In the case of Object obj, obj is a reference to an object. Since == tests whether two object references have the same value, it is testing whether they refer to the identical object (i.e., that the references are equal).
回答2:
== intuitively work differently on primitive types. Its just that way in the language.
If you think about it in C++ terms, references are pointers and == does pointer comparison.
int* myPtr1 = new int(5);
int* myPtr2 = new int(6);
myPtr1 == myPtr2;
来源：https://stackoverflow.com/questions/7097886/operator-for-primitive-data-types