hashcode and equals in java

); }Comparative Substance:When comparing variables with "= =" in Java, the system uses the values stored in the "stack" of variables as the basis for comparison.The base data type is stored in the stack as its content value, and the object type is the address that is stored in the stack, which points to the object in the heap.The object class in the Java.lang package has the public boolean equals (Object

This is the desired result if any of the following conditions are met:Each instance of a class is inherently unique.Does not care if the class provides a "logical equality" test function.The superclass has overridden equals, and the behavior inherited from the superclass is also appropriate for subclasses.Class is private or package-level private, it can be determined that its Equals method is never called.

distinguish between these, kinds of equality. One of the "identical" when talking about equality of references and the word "equal" when Talking about a distinct objects that has the same content. To test-nonidentical objects for equality, pass one of the them to the Equals () method of the other: All objects inherit a Equals () method (from Object), but the default implementa‐tion simply uses = =

Data types in Java can be divided into two categories: 1. The basic data type, also known as the original data type .Byte,short,char,int,long,float,double,boolean the comparison between them, apply the double equals sign (= =), compare their values. 2. Composite data type (Class) when they compare with (= =), they compare the storage address in memory , so unless it is the same new object, their comparison

Equals ()Implement Equals ()Parameter must be an object, not a perimeter classWhen overriding Equals (), also overwrite the corresponding hashcode (), consistent with Equals ()Also note that the default value of string is nullpublic class Person {private String name;private

Always overwrite hashcode when Java overrides equals Recent Learning Java Basics, encounter Java coverage equals always have to cover hashcode when there are many questions, and collea

Data types in Java have basic data types and reference data types.The basic data types are: Int,char,float,long,double,boolean,byte,short (Note: string is not the base data type), and the comparison between the base data types is "= =".Reference data types include: Integer,char,float,long,double,boolean,byte,short. The reference data type "= =" compares their storage addresses in memory, and equals compares

=offset; - intj =Anotherstring.offset; - while(n--! = 0) { in if(v1[i++]! = v2[j++]) - return false ; to } + return true ; - } the } * return false; $}From the above you can see the case where the java.lang.String.equals (Object AnObject) method returns true: Compare yourself with yourself; Two objects are string and the contents are the same. To be aware of:

Java equals method and = usage, javaequals Equals method usage and = usage in java (refer to 1)The equals method is a java. lang. Object Class method.Two usage instructions:(1) For string variables, the comparison method is differ

Java has the concept of object and object reference, in string, = = comparison is a reference, equals compares the object's specific value.string S1 = new String ("abc");String s2 = new String ("abc");System.out.println (S1 = = s2);System.out.println (s1.equals (S2));The above code will print a false and a true. This is easy to understand because S1 and S2 are re

Reprint Please specify source: http://blog.csdn.net/dmk877/article/details/49420141Whether you are a novice programmer or an old hand, you must feel particularly familiar with string, because the string class has been learned since we learned Java basics, but is the string type as simple as we think? In fact, the knowledge point of String type is still more. Today and everyone to discuss, about the string of some easily confusing place, nonsense not m

, and if there is no Override, the call is called directly from the Equals () method inherited from the object class, and Equals () is used The default implementation of the method is to compare whether two objects are equal. Each class can therefore override the Equals () method inherited from the object class as needed.For a class in the API document, if a clas

The equals method is a Java. Lang. Object Class method. There are two usage instructions: (1) For string variables, the comparison method is different when "=" and "equals ()" are used to compare strings. "=" Compares the values of the two variables, that is, the first address of the two objects in the memory. "Equals

Equals method in the Animal class, this method evaluates name, first D1 instanceof Animal must be true, because the dog class is a subclass of Animal, So the if condition does not block out D1, because the name of two objects is the same, so the return value is true, but the real result is false, because they do not belong to the same class! As for the second why is false, here will not be explained!Then we come back to see the correct wording, This.

are judged equal, no difference to basic variables, except for dynamic variables (that is, objects): = =: values are equal. For object references, that is, the reference value is equal to the address. That is, if object a A, a==b indicates whether the addresses of a and b are equal. Equals (): Is the method of object, and its implementation is return this = = Inputobject. However, this method is often overridden, such as String,in

The difference between the Equals method in Java and the "= =": The Equals method is the Java.lang.Object class method. There are two ways to use these instructions: (1) For string variables, the comparison method differs when comparing strings using the "= =" and "Equals ()" methods. "= =" compares the values of two v

The data types in Java can be divided into two categories:1. The basic data type, also known as the original data type . Byte,short,char,int,long,float,double,booleanThe comparison between them, applying the double equals sign (= =), compares their values.2. Composite data type (Class)(1) when they compare with (= =) , they compare the storage address in memory, so, unless it is the same new object, their c

A brief introduction to the Equals method is a method of the Java.lang.Object class with two usages: first, when you compare strings using the "= =" and "Equals ()" Methods for string variables, their comparison methods are different. 1, "= =" compares the value of two variables themselves, that is, the first address of two objects in memory. (in Java, the first

There is no difference between the two types of variables of the basic type. Why is it possible to compare variables of the reference type?What about different results? Remember the pointer in C ++? This is a bit like deep copy and shortest copy.The reference of an object in Java is a pointer, but the Java language itself does not provide any syntax for direct access to it.Because when we use a variable of

for the other packaging classes are similar.In the Java specification, its use of the Equals () method must follow several rules:The Equals method implements an equality relationship on a non-null object reference:1, reflexivity: for any non-null reference value X,x.equals (x) should return true.2. Symmetry: for any non-null reference value x and Y, x.equals (y)