equals

问题 Basically, I need to compare two arrays and check if they have the same values in the same positions (recursively of course). I get an error with my current code: Array out of index exception:20 The code I have right now looks as follows: private boolean equalsHelper(int[] first, int[] second, int iStart, int iEnd){ if (first[iStart] == second[iStart]){ if (equalsHelper(first,second,(iStart+1),iEnd)) { return true; } } if (iStart == iEnd){ return first[iEnd] == second[iEnd]; } return false; }

问题 Is it possible to compare 2 objects of same class without overriding equals method.. ? If yes, please let me know how.. ? According to me, it is not possible to compare variables of 2 different objects of same class without overriding because object contains memory address and not the variable value. class A { int x; A(int x) { this.x=x; } } A a1=new A(5); A a2=new A(4); Can we compare a1 & a2 using equals method and without overriding it.. ? Also the value should be compared not the address

问题 I modified some code in my current web project to add Spring transaction management. Everything works just fine when I deploy it in Eclipse or even when I call a "Maven clean" and a "Maven install" in my workspace. However when my continuous integration server (jenkins) tries to redeploy it on my distant server I get a java.lang.VerifyError and it fails: maven-glassfish-plugin:2.1:deploy (default-cli) @ myApp --- [INFO] asadmin --host localhost --port 4848 --user admin --passwordfile C:

问题 With respect to 3 contracts mentioned below: 1) Whenever hashCode() is invoked on the same object more than once during an execution of an application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application. From this statement, i understand that, In a single execution of an application,

问题 http://shoes4school.project-x.me/get-involved.html Can someone please tell me what i'm doing wrong the the jQuery column faux... I can not get it to work after trying several different methods... The code i'm using is... my url is above $j(".content-block").height(Math.max($("#right").height(), $(".content-block").height())); 回答1: How to faux columns on webpage (function($){ // add a new method to JQuery $.fn.equalHeight = function() { // find the tallest height in the collection // that was

问题 I was make some code and found that objects ar eno equals - it is trivial question but not understand how default equals works. class A { String id; public A(String id) { this.id = id; } public static void main(String args[]) { A a = new A("1"); A b = new A("1"); System.out.println(a.id); System.out.println(b.id); System.out.println(a.equals(b)); } } Result is: 1 1 false But I want to have a.equals(b) == true why it is false ? 回答1: Your class currently extends only Object class and in Object

问题 I have a class that imlements IEquatable<T> . Is it necessary to do a refrence check in Equals() or is it taken care of in the framework? class Foo : IEquatable<Foo> { int value; Bar system; bool Equals(Foo other) { return this == other || ( value == other.value && system.Equals(other.system) ); } } In the above example is the this==other statement superfluous or necessary? Update 1 I understand I need to correct the code as follows: bool Equals(Foo other) { if( other==null ) { return false;

问题 After reading this question Why do "int" and "sbyte" GetHashCode functions generate different values? I wanted to dig further and found following behavior: sbyte i = 1; int j = 1; object.Equals(i, j) //false (1) object.Equals(j, i) //false (2) i.Equals(j) //false (3) j.Equals(i) //true (4) i == j //true (5) j == i //true (6) i.GetHashCode() == j.GetHashCode() //false (7) Difference between (3) and (4) breaks the requirement that Equals should be symmetric. Difference between (2) and (4) is

问题 Everytime I write some data class, I usually spend so much time writing the IEquatable implementation. The last class I wrote was something like: public class Polygon { public Point[] Vertices { get; set; } } Implementing IEquatable was exaustive. Surely C#3.0/LINQ helps a lot, but the vertices can be shifted and/or in the reverse order, and that adds a lot of complexity to the Equals method. After many unit tests, and corresponding implementation, I gave up, and changed my application to

问题 I wanted to make sure about something in Java: If I have a Character or an Integer or a Long and those sort of things, should I use equals or is == sufficient? I know that with strings there are no guarantees that there is only one instance of each unique string, but I'm not sure about other boxed types. My intuition is to use equals, but I want to make sure I'm not wasting performance. 回答1: EDIT: The spec makes some guarantees for boxing conversions. From section 5.1.7: If the value p being